From 882b9ea6d25b8d85fdb49d9af8b951fef0969826 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@esss.se>
Date: Sun, 18 Sep 2022 21:58:40 +0200
Subject: [PATCH 01/10] progress towards removing to_widget

---
 src/plopp/interactive.py   | 57 +++++++++++++++++++++++---------------
 src/plopp/plot.py          | 22 ++++-----------
 src/plopp/toolbar.py       | 20 +++++++------
 src/plopp/view.py          |  4 +--
 src/plopp/widgets/slice.py | 51 ++++++++++++++++++++++------------
 5 files changed, 86 insertions(+), 68 deletions(-)

diff --git a/src/plopp/interactive.py b/src/plopp/interactive.py
index ce0a977c..5795aec7 100644
--- a/src/plopp/interactive.py
+++ b/src/plopp/interactive.py
@@ -5,26 +5,37 @@
 from .figure import Figure
 from .toolbar import Toolbar
 
-import ipywidgets as ipw
+# import ipywidgets as ipw
+from ipywidgets import VBox, HBox
 
+# class SideBar(Displayable):
+#     def __init__(self, *args, **kwargs):
+#         self._children = list(*args, **kwargs)
+#         super().__init__(self._children)
 
-class SideBar(list, Displayable):
+#     # def to_widget(self):
+#     #     return VBox([child.to_widget() for child in self])
 
-    def to_widget(self):
-        return ipw.VBox([child.to_widget() for child in self])
 
+class InteractiveFig(Figure, VBox):
 
-class InteractiveFig(Figure, Displayable):
+    def __init__(self, *args, **kwargs):
+
+        Figure.__init__(self, *args, **kwargs)
+        VBox.__init__(self, [
+            self.top_bar,
+            HBox([self.left_bar, self._fig.canvas, self.right_bar]), self.bottom_bar
+        ])
 
     def _post_init(self):
 
         self._fig.canvas.toolbar_visible = False
         self._fig.canvas.header_visible = False
 
-        self.left_bar = SideBar()
-        self.right_bar = SideBar()
-        self.bottom_bar = SideBar()
-        self.top_bar = SideBar()
+        self.left_bar = VBox()
+        self.right_bar = VBox()
+        self.bottom_bar = HBox()
+        self.top_bar = HBox()
 
         self.toolbar = Toolbar(
             tools={
@@ -37,20 +48,20 @@ def _post_init(self):
             })
         self._fig.canvas.toolbar_visible = False
         self._fig.canvas.header_visible = False
-        self.left_bar.append(self.toolbar)
-
-    def to_widget(self) -> ipw.Widget:
-        """
-        Convert the Matplotlib figure to a widget.
-        """
-        return ipw.VBox([
-            self.top_bar.to_widget(),
-            ipw.HBox([
-                self.left_bar.to_widget(), self._fig.canvas,
-                self.right_bar.to_widget()
-            ]),
-            self.bottom_bar.to_widget()
-        ])
+        self.left_bar.children = tuple([self.toolbar])
+
+    # def to_widget(self) -> Widget:
+    #     """
+    #     Convert the Matplotlib figure to a widget.
+    #     """
+    #     return VBox([
+    #         self.top_bar.to_widget(),
+    #         HBox([
+    #             self.left_bar.to_widget(), self._fig.canvas,
+    #             self.right_bar.to_widget()
+    #         ]),
+    #         self.bottom_bar.to_widget()
+    #     ])
 
     def home(self):
         self._autoscale()
diff --git a/src/plopp/plot.py b/src/plopp/plot.py
index 0cdbd80d..d4b5bb9a 100644
--- a/src/plopp/plot.py
+++ b/src/plopp/plot.py
@@ -1,26 +1,14 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright (c) 2022 Scipp contributors (https://github.com/scipp)
 
-from .displayable import Displayable
+from ipywidgets import VBox, HBox
 
 
-def _maybe_to_widget(view):
-    return view.to_widget() if hasattr(view, "to_widget") else view
-
-
-class Plot(Displayable):
+class Plot(VBox):
 
     def __init__(self, views):
         self.views = views
-
-    def to_widget(self):
-        """
-        """
-        import ipywidgets as ipw
-        out = []
+        children = []
         for view in self.views:
-            if isinstance(view, (list, tuple)):
-                out.append(ipw.HBox([_maybe_to_widget(v) for v in view]))
-            else:
-                out.append(_maybe_to_widget(view))
-        return ipw.VBox(out)
+            children.append(HBox(view) if isinstance(view, (list, tuple)) else view)
+        return super().__init__(children)
diff --git a/src/plopp/toolbar.py b/src/plopp/toolbar.py
index f984ebd1..4b8810d6 100644
--- a/src/plopp/toolbar.py
+++ b/src/plopp/toolbar.py
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright (c) 2022 Scipp contributors (https://github.com/scipp)
 
+from ipywidgets import Button, VBox
 from functools import partial
 from typing import Callable
 
@@ -33,7 +34,7 @@ def __init__(self, callback: Callable, value: bool = False, **kwargs):
         cases, we need to toggle the button color without triggering the callback
         function.
         """
-        from ipywidgets import Button
+        # from ipywidgets import Button
         self.widget = Button(**{**LAYOUT_STYLE, **kwargs})
         self._callback = callback
         self.widget.on_click(self)
@@ -70,7 +71,7 @@ def _toggle(self):
 }
 
 
-class Toolbar(Displayable):
+class Toolbar(VBox):
     """
     Custom toolbar with additional buttons for controlling log scales and
     normalization, and with back/forward buttons removed.
@@ -82,10 +83,11 @@ def __init__(self, tools=None):
             tool = TOOL_LIBRARY[key](callback=callback)
             setattr(self, key, tool)
             self._widgets[key] = tool.widget
-
-    def to_widget(self):
-        """
-        Return the VBox container
-        """
-        from ipywidgets import VBox
-        return VBox(tuple(self._widgets.values()))
+        super().__init__(tuple(self._widgets.values()))
+
+    # def to_widget(self):
+    #     """
+    #     Return the VBox container
+    #     """
+    #     from ipywidgets import VBox
+    #     return VBox(tuple(self._widgets.values()))
diff --git a/src/plopp/view.py b/src/plopp/view.py
index 25865d63..c69e3ec2 100644
--- a/src/plopp/view.py
+++ b/src/plopp/view.py
@@ -1,11 +1,11 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright (c) 2022 Scipp contributors (https://github.com/scipp)
 
-from abc import ABC, abstractmethod
+from abc import abstractmethod
 import uuid
 
 
-class View(ABC):
+class View:
 
     def __init__(self, *nodes):
         self.id = str(uuid.uuid1())
diff --git a/src/plopp/widgets/slice.py b/src/plopp/widgets/slice.py
index d3a1fb60..2d9aac16 100644
--- a/src/plopp/widgets/slice.py
+++ b/src/plopp/widgets/slice.py
@@ -38,7 +38,7 @@ def render(self):
             self._update(new_coords=new_values.meta)
 
 
-class SliceWidget(Displayable):
+class SliceWidget(ipw.VBox):
     """
     Widgets containing a slider for each of the input's dimensions, as well as
     buttons to modify the currently displayed axes.
@@ -50,6 +50,7 @@ def __init__(self, data_array, dims: list):
         self._slider_dims = dims
         self.controls = {}
         self.view = None
+        children = []
 
         for dim in dims:
             slider = ipw.IntSlider(step=1,
@@ -63,22 +64,38 @@ def __init__(self, data_array, dims: list):
                                              description="Continuous update",
                                              indent=False,
                                              layout={"width": "20px"})
+            label = ipw.Label()
             ipw.jslink((continuous_update, 'value'), (slider, 'continuous_update'))
 
-            self.controls[dim] = {'continuous': continuous_update, 'slider': slider}
-
-        for dim in self._slider_dims:
-            row = list(self.controls[dim].values())
-            self._container.append(ipw.HBox(row))
-
-    def to_widget(self) -> ipw.Widget:
-        """
-        Gather all widgets in a single container box.
-        """
-        out = ipw.VBox(self._container)
-        if self.view is not None:
-            out = ipw.HBox([out, self.view.to_widget()])
-        return out
+            self.controls[dim] = {
+                'continuous': continuous_update,
+                'slider': slider,
+                'label': label,
+                'coord': data_array.meta[dim]
+            }
+            # slider.observe(self._update_label, names='value')
+            children.append(ipw.HBox([continuous_update, slider, label]))
+
+        super().__init__(children)
+
+        # for dim in self._slider_dims:
+        #     row = list(self.controls[dim].values())
+        #     self._container.append(ipw.HBox(row))
+
+    # def to_widget(self) -> ipw.Widget:
+    #     """
+    #     Gather all widgets in a single container box.
+    #     """
+    #     out = ipw.VBox(self._container)
+    #     if self.view is not None:
+    #         out = ipw.HBox([out, self.view.to_widget()])
+    #     return out
+
+    def _update_label(self, change):
+        dim = change['owner'].description
+        coord = self.controls[dim]['coord']
+        self.controls[dim]['label'].value = value_to_string(
+            coord[dim, change['new']].values) + str(coord.unit)
 
     def observe(self, callback: Callable, **kwargs):
         for dim in self.controls:
@@ -88,8 +105,8 @@ def observe(self, callback: Callable, **kwargs):
     def value(self) -> dict:
         return {dim: self.controls[dim]['slider'].value for dim in self._slider_dims}
 
-    def make_view(self, *nodes):
-        self.view = SliceView(self._slider_dims, *nodes)
+    # def make_view(self, *nodes):
+    #     self.view = SliceView(self._slider_dims, *nodes)
 
 
 @node

From e45a99098ed95206596fef6973c818c643427a7e Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@esss.se>
Date: Sun, 18 Sep 2022 23:01:29 +0200
Subject: [PATCH 02/10] stuck on slice widget creation

---
 src/plopp/widgets/slice.py | 46 +++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 23 deletions(-)

diff --git a/src/plopp/widgets/slice.py b/src/plopp/widgets/slice.py
index 2d9aac16..50202cbf 100644
--- a/src/plopp/widgets/slice.py
+++ b/src/plopp/widgets/slice.py
@@ -10,32 +10,31 @@
 import ipywidgets as ipw
 from typing import Callable
 
+# class SliceView(View):
 
-class SliceView(View):
+#     def __init__(self, dims, *nodes):
+#         super().__init__(*nodes)
+#         self._labels = {dim: ipw.Label() for dim in dims}
 
-    def __init__(self, dims, *nodes):
-        super().__init__(*nodes)
-        self._labels = {dim: ipw.Label() for dim in dims}
+#     def to_widget(self) -> ipw.Widget:
+#         self.render()
+#         return ipw.VBox(list(self._labels.values()))
 
-    def to_widget(self) -> ipw.Widget:
-        self.render()
-        return ipw.VBox(list(self._labels.values()))
+#     def _update(self, new_coords):
+#         for dim, lab in self._labels.items():
+#             if dim in new_coords:
+#                 lab.value = value_to_string(new_coords[dim].values) + str(
+#                     new_coords[dim].unit)
 
-    def _update(self, new_coords):
-        for dim, lab in self._labels.items():
-            if dim in new_coords:
-                lab.value = value_to_string(new_coords[dim].values) + str(
-                    new_coords[dim].unit)
+#     def notify_view(self, message):
+#         node_id = message["node_id"]
+#         new_values = self._graph_nodes[node_id].request_data()
+#         self._update(new_values.meta)
 
-    def notify_view(self, message):
-        node_id = message["node_id"]
-        new_values = self._graph_nodes[node_id].request_data()
-        self._update(new_values.meta)
-
-    def render(self):
-        for n in self._graph_nodes.values():
-            new_values = n.request_data()
-            self._update(new_coords=new_values.meta)
+#     def render(self):
+#         for n in self._graph_nodes.values():
+#             new_values = n.request_data()
+#             self._update(new_coords=new_values.meta)
 
 
 class SliceWidget(ipw.VBox):
@@ -45,6 +44,7 @@ class SliceWidget(ipw.VBox):
     """
 
     def __init__(self, data_array, dims: list):
+        print("INIIIIT")
 
         self._container = []
         self._slider_dims = dims
@@ -73,7 +73,7 @@ def __init__(self, data_array, dims: list):
                 'label': label,
                 'coord': data_array.meta[dim]
             }
-            # slider.observe(self._update_label, names='value')
+            slider.observe(self._update_label, names='value')
             children.append(ipw.HBox([continuous_update, slider, label]))
 
         super().__init__(children)
@@ -97,7 +97,7 @@ def _update_label(self, change):
         self.controls[dim]['label'].value = value_to_string(
             coord[dim, change['new']].values) + str(coord.unit)
 
-    def observe(self, callback: Callable, **kwargs):
+    def observe(self, callback: Callable, ignored, **kwargs):
         for dim in self.controls:
             self.controls[dim]['slider'].observe(callback, **kwargs)
 

From 543a15f4e2ea3d8c0a731c2bc1d189d75aea7b99 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@esss.se>
Date: Mon, 19 Sep 2022 11:36:40 +0200
Subject: [PATCH 03/10] make slider coord update local to slider

---
 src/plopp/widgets/slice.py | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/src/plopp/widgets/slice.py b/src/plopp/widgets/slice.py
index 50202cbf..ed146bd6 100644
--- a/src/plopp/widgets/slice.py
+++ b/src/plopp/widgets/slice.py
@@ -37,6 +37,13 @@
 #             self._update(new_coords=new_values.meta)
 
 
+def _coord_to_string(coord):
+    out = value_to_string(coord.values)
+    if coord.unit is not None:
+        out += f" [{coord.unit}]"
+    return out
+
+
 class SliceWidget(ipw.VBox):
     """
     Widgets containing a slider for each of the input's dimensions, as well as
@@ -44,7 +51,7 @@ class SliceWidget(ipw.VBox):
     """
 
     def __init__(self, data_array, dims: list):
-        print("INIIIIT")
+        # print("INIIIIT")
 
         self._container = []
         self._slider_dims = dims
@@ -53,25 +60,26 @@ def __init__(self, data_array, dims: list):
         children = []
 
         for dim in dims:
+            coord = data_array.meta[dim]
             slider = ipw.IntSlider(step=1,
                                    description=dim,
                                    min=0,
                                    max=data_array.sizes[dim],
                                    continuous_update=True,
-                                   readout=True,
-                                   layout={"width": "400px"})
+                                   readout=False,
+                                   layout={"width": "200px"})
             continuous_update = ipw.Checkbox(value=True,
                                              description="Continuous update",
                                              indent=False,
                                              layout={"width": "20px"})
-            label = ipw.Label()
+            label = ipw.Label(value=_coord_to_string(coord[dim, 0]))
             ipw.jslink((continuous_update, 'value'), (slider, 'continuous_update'))
 
             self.controls[dim] = {
                 'continuous': continuous_update,
                 'slider': slider,
                 'label': label,
-                'coord': data_array.meta[dim]
+                'coord': coord
             }
             slider.observe(self._update_label, names='value')
             children.append(ipw.HBox([continuous_update, slider, label]))
@@ -93,13 +101,12 @@ def __init__(self, data_array, dims: list):
 
     def _update_label(self, change):
         dim = change['owner'].description
-        coord = self.controls[dim]['coord']
-        self.controls[dim]['label'].value = value_to_string(
-            coord[dim, change['new']].values) + str(coord.unit)
+        coord = self.controls[dim]['coord'][dim, change['new']]
+        self.controls[dim]['label'].value = _coord_to_string(coord)
 
-    def observe(self, callback: Callable, ignored, **kwargs):
-        for dim in self.controls:
-            self.controls[dim]['slider'].observe(callback, **kwargs)
+    # def observe(self, callback: Callable, ignored, **kwargs):
+    #     for dim in self.controls:
+    #         self.controls[dim]['slider'].observe(callback, **kwargs)
 
     @property
     def value(self) -> dict:

From 6bf2e3e1d28960feec7ea624c4e3bac09a794064 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@esss.se>
Date: Mon, 19 Sep 2022 12:47:46 +0200
Subject: [PATCH 04/10] make mask checkboxes a widget

---
 src/plopp/__init__.py           |  2 +-
 src/plopp/model.py              | 11 +++++++
 src/plopp/widgets/__init__.py   |  1 -
 src/plopp/widgets/checkboxes.py | 57 +++++++++------------------------
 src/plopp/widgets/slice.py      | 56 +++++---------------------------
 src/plopp/widgets/widgetnode.py | 10 ------
 tests/graph_nodes_test.py       | 16 ++++-----
 7 files changed, 43 insertions(+), 110 deletions(-)
 delete mode 100644 src/plopp/widgets/widgetnode.py

diff --git a/src/plopp/__init__.py b/src/plopp/__init__.py
index 394a3119..45dc97e6 100644
--- a/src/plopp/__init__.py
+++ b/src/plopp/__init__.py
@@ -15,7 +15,7 @@
 
 from .graph import show_graph
 from .plot import Plot
-from .model import Node, node, input_node
+from .model import Node, node, input_node, widget_node
 from .wrappers import plot, figure
 
 from . import data
diff --git a/src/plopp/model.py b/src/plopp/model.py
index eeb8a6ce..5dbebfe1 100644
--- a/src/plopp/model.py
+++ b/src/plopp/model.py
@@ -52,3 +52,14 @@ def make_node(*args, **kwargs):
 
 def input_node(obj):
     return Node(lambda: obj)
+
+
+def widget_node(widget):
+    n = Node(func=lambda: widget.value)
+    # TODO: Our custom widgets have a 'watch' method instead of 'observe' because
+    # inheriting from VBox causes errors when overriding the 'observe' method
+    # (see https://bit.ly/3SggPVS).
+    # We need to be careful that widgets don't get a method named 'watch' in the future.
+    func = widget.watch if hasattr(widget, 'watch') else widget.observe
+    func(n.notify_children, names="value")
+    return n
diff --git a/src/plopp/widgets/__init__.py b/src/plopp/widgets/__init__.py
index 1230455a..1b8c87b4 100644
--- a/src/plopp/widgets/__init__.py
+++ b/src/plopp/widgets/__init__.py
@@ -6,4 +6,3 @@
 # from .masks import MaskWidget, hide_masks
 from .checkboxes import Checkboxes
 from .slice import SliceWidget, slice_dims
-from .widgetnode import widget_node
diff --git a/src/plopp/widgets/checkboxes.py b/src/plopp/widgets/checkboxes.py
index 2f8b5a14..274c4096 100644
--- a/src/plopp/widgets/checkboxes.py
+++ b/src/plopp/widgets/checkboxes.py
@@ -1,24 +1,20 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright (c) 2022 Scipp contributors (https://github.com/scipp)
 
-from functools import partial
 from html import escape
 import ipywidgets as ipw
 from typing import Callable
-from ..displayable import Displayable
 
 
-class Checkboxes(Displayable):
+class Checkboxes(ipw.HBox):
     """
     Widget providing a list of checkboxes, along with a button to toggle them all.
     """
 
     def __init__(self, entries: list, description=""):
-
-        self._callback = None
-
         self.checkboxes = {}
         self._lock = False
+        self._description = ipw.Label(value=description)
 
         for key in entries:
             self.checkboxes[key] = ipw.Checkbox(value=True,
@@ -26,54 +22,31 @@ def __init__(self, entries: list, description=""):
                                                 indent=False,
                                                 layout={"width": "initial"})
 
-        if len(self.checkboxes):
-            self._description = ipw.Label(value=description)
+        to_hbox = [
+            self._description,
+            ipw.HBox(list(self.checkboxes.values()),
+                     layout=ipw.Layout(flex_flow='row wrap'))
+        ]
 
+        if len(self.checkboxes):
             # Add a master button to control all masks in one go
             self.toggle_all_button = ipw.ToggleButton(value=True,
                                                       description="De-select all",
                                                       disabled=False,
                                                       button_style="",
-                                                      layout={"width": "100px"})
+                                                      layout={"width": "initial"})
+            for cbox in self.checkboxes.values():
+                ipw.jsdlink((self.toggle_all_button, 'value'), (cbox, 'value'))
+            to_hbox.insert(1, self.toggle_all_button)
 
-    def to_widget(self) -> ipw.Widget:
-        """
-        Gather all widgets in a single container box.
-        """
-        out = ipw.HBox()
-        if len(self.checkboxes):
-            out.children = [
-                self._description, self.toggle_all_button,
-                ipw.HBox(list(self.checkboxes.values()))
-            ]
-        return out
+        super().__init__(to_hbox)
 
-    def observe(self, callback: Callable, **kwargs):
+    def watch(self, callback: Callable, **kwargs):
         for chbx in self.checkboxes.values():
-            chbx.observe(self._toggle, **kwargs)
-        if len(self.checkboxes):
-            self.toggle_all_button.observe(self._toggle_all, **kwargs)
-        self._callback = partial(callback, None)
+            chbx.observe(callback, **kwargs)
 
     @property
     def value(self) -> dict:
         """
         """
         return {key: chbx.value for key, chbx in self.checkboxes.items()}
-
-    def _toggle(self, _):
-        if self._lock:
-            return
-        self._callback()
-
-    def _toggle_all(self, change: dict):
-        """
-        A main button to hide or show all masks at once.
-        """
-        self._lock = True
-        for key in self.checkboxes:
-            self.checkboxes[key].value = change["new"]
-        change["owner"].description = ("De-select all"
-                                       if change["new"] else "Select all")
-        self._lock = False
-        self._callback()
diff --git a/src/plopp/widgets/slice.py b/src/plopp/widgets/slice.py
index ed146bd6..74e612ee 100644
--- a/src/plopp/widgets/slice.py
+++ b/src/plopp/widgets/slice.py
@@ -5,37 +5,10 @@
 from ..tools import value_to_string
 from ..view import View
 from ..model import node
-from ..displayable import Displayable
 
 import ipywidgets as ipw
 from typing import Callable
 
-# class SliceView(View):
-
-#     def __init__(self, dims, *nodes):
-#         super().__init__(*nodes)
-#         self._labels = {dim: ipw.Label() for dim in dims}
-
-#     def to_widget(self) -> ipw.Widget:
-#         self.render()
-#         return ipw.VBox(list(self._labels.values()))
-
-#     def _update(self, new_coords):
-#         for dim, lab in self._labels.items():
-#             if dim in new_coords:
-#                 lab.value = value_to_string(new_coords[dim].values) + str(
-#                     new_coords[dim].unit)
-
-#     def notify_view(self, message):
-#         node_id = message["node_id"]
-#         new_values = self._graph_nodes[node_id].request_data()
-#         self._update(new_values.meta)
-
-#     def render(self):
-#         for n in self._graph_nodes.values():
-#             new_values = n.request_data()
-#             self._update(new_coords=new_values.meta)
-
 
 def _coord_to_string(coord):
     out = value_to_string(coord.values)
@@ -51,8 +24,6 @@ class SliceWidget(ipw.VBox):
     """
 
     def __init__(self, data_array, dims: list):
-        # print("INIIIIT")
-
         self._container = []
         self._slider_dims = dims
         self.controls = {}
@@ -86,35 +57,24 @@ def __init__(self, data_array, dims: list):
 
         super().__init__(children)
 
-        # for dim in self._slider_dims:
-        #     row = list(self.controls[dim].values())
-        #     self._container.append(ipw.HBox(row))
-
-    # def to_widget(self) -> ipw.Widget:
-    #     """
-    #     Gather all widgets in a single container box.
-    #     """
-    #     out = ipw.VBox(self._container)
-    #     if self.view is not None:
-    #         out = ipw.HBox([out, self.view.to_widget()])
-    #     return out
-
     def _update_label(self, change):
         dim = change['owner'].description
         coord = self.controls[dim]['coord'][dim, change['new']]
         self.controls[dim]['label'].value = _coord_to_string(coord)
 
-    # def observe(self, callback: Callable, ignored, **kwargs):
-    #     for dim in self.controls:
-    #         self.controls[dim]['slider'].observe(callback, **kwargs)
+    def watch(self, callback: Callable, **kwargs):
+        """
+        TODO: Cannot name this method 'observe' when inheriting from HBox, so we name
+        it 'watch' instead (see https://bit.ly/3SggPVS). We need to be careful that
+        widgets don't get a method named 'watch' in the future.
+        """
+        for dim in self.controls:
+            self.controls[dim]['slider'].observe(callback, **kwargs)
 
     @property
     def value(self) -> dict:
         return {dim: self.controls[dim]['slider'].value for dim in self._slider_dims}
 
-    # def make_view(self, *nodes):
-    #     self.view = SliceView(self._slider_dims, *nodes)
-
 
 @node
 def slice_dims(data_array: DataArray, slices: dict) -> DataArray:
diff --git a/src/plopp/widgets/widgetnode.py b/src/plopp/widgets/widgetnode.py
deleted file mode 100644
index af507247..00000000
--- a/src/plopp/widgets/widgetnode.py
+++ /dev/null
@@ -1,10 +0,0 @@
-# SPDX-License-Identifier: BSD-3-Clause
-# Copyright (c) 2022 Scipp contributors (https://github.com/scipp)
-
-from ..model import Node
-
-
-def widget_node(widget):
-    n = Node(func=lambda: widget.value)
-    widget.observe(n.notify_children, names="value")
-    return n
diff --git a/tests/graph_nodes_test.py b/tests/graph_nodes_test.py
index b56ae81d..6719ac0f 100644
--- a/tests/graph_nodes_test.py
+++ b/tests/graph_nodes_test.py
@@ -2,8 +2,8 @@
 # Copyright (c) 2022 Scipp contributors (https://github.com/scipp)
 
 import scipp as sc
-from plopp import Plot, figure, input_node, node
-from plopp.widgets import widget_node, Checkboxes, SliceWidget, slice_dims
+from plopp import Plot, figure, node, input_node, widget_node
+from plopp.widgets import Checkboxes, SliceWidget, slice_dims
 from plopp.data import dense_data_array, dense_dataset
 import ipywidgets as ipw
 
@@ -60,7 +60,7 @@ def test_2d_image_smoothing_slider():
     smooth_node = node(gaussian_filter)(a, sigma=sigma_node)
 
     fig = figure(smooth_node)
-    Plot([fig, sl])
+    Plot([fig.to_widget(), sl])
     sl.value = 5
 
 
@@ -76,7 +76,7 @@ def test_2d_image_with_masks():
 
     masks_node = hide_masks(a, w)
     fig = figure(masks_node)
-    Plot([fig, widget])
+    Plot([fig.to_widget(), widget])
     widget.toggle_all_button.value = False
 
 
@@ -95,7 +95,7 @@ def test_two_1d_lines_with_masks():
     node_masks_a = hide_masks(a, w)
     node_masks_b = hide_masks(b, w)
     fig = figure(node_masks_a, node_masks_b)
-    Plot([fig, widget])
+    Plot([fig.to_widget(), widget])
     widget.toggle_all_button.value = False
 
 
@@ -107,7 +107,7 @@ def test_node_sum_data_along_y():
 
     fig1 = figure(a)
     fig2 = figure(s)
-    Plot([[fig1, fig2]])
+    Plot([[fig1.to_widget(), fig2.to_widget()]])
 
 
 def test_slice_3d_cube():
@@ -120,7 +120,7 @@ def test_slice_3d_cube():
     sl.make_view(slice_node)
 
     fig = figure(slice_node)
-    Plot([fig, sl])
+    Plot([fig.to_widget(), sl])
     sl.controls["zz"]["slider"].value = 10
 
 
@@ -139,5 +139,5 @@ def test_3d_image_slicer_with_connected_side_histograms():
 
     fx = figure(histx)
     fy = figure(histy)
-    Plot([[fx, fy], fig, sl])
+    Plot([[fx.to_widget(), fy.to_widget()], fig.to_widget(), sl])
     sl.controls["zz"]["slider"].value = 10

From 36b82d614cb4ef363a10397e206596dbae3a7b29 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@esss.se>
Date: Mon, 19 Sep 2022 12:55:14 +0200
Subject: [PATCH 05/10] cleanup

---
 src/plopp/displayable.py | 25 -------------------------
 src/plopp/interactive.py | 22 ----------------------
 src/plopp/toolbar.py     |  9 ---------
 src/plopp/view.py        |  4 ----
 4 files changed, 60 deletions(-)
 delete mode 100644 src/plopp/displayable.py

diff --git a/src/plopp/displayable.py b/src/plopp/displayable.py
deleted file mode 100644
index 1268a378..00000000
--- a/src/plopp/displayable.py
+++ /dev/null
@@ -1,25 +0,0 @@
-# SPDX-License-Identifier: BSD-3-Clause
-# Copyright (c) 2022 Scipp contributors (https://github.com/scipp)
-
-try:
-    from ipywidgets import Widget
-except ImportError:
-    Widget = None
-
-
-class Displayable:
-
-    if hasattr(Widget, '_repr_mimebundle_'):
-
-        def _repr_mimebundle_(self, include=None, exclude=None):
-            """
-            Mimebundle display representation for jupyter notebooks.
-            """
-            return self.to_widget()._repr_mimebundle_(include=include, exclude=exclude)
-    else:
-
-        def _ipython_display_(self):
-            """
-            IPython display representation for Jupyter notebooks.
-            """
-            return self.to_widget()._ipython_display_()
diff --git a/src/plopp/interactive.py b/src/plopp/interactive.py
index 5795aec7..fd418b88 100644
--- a/src/plopp/interactive.py
+++ b/src/plopp/interactive.py
@@ -5,17 +5,8 @@
 from .figure import Figure
 from .toolbar import Toolbar
 
-# import ipywidgets as ipw
 from ipywidgets import VBox, HBox
 
-# class SideBar(Displayable):
-#     def __init__(self, *args, **kwargs):
-#         self._children = list(*args, **kwargs)
-#         super().__init__(self._children)
-
-#     # def to_widget(self):
-#     #     return VBox([child.to_widget() for child in self])
-
 
 class InteractiveFig(Figure, VBox):
 
@@ -50,19 +41,6 @@ def _post_init(self):
         self._fig.canvas.header_visible = False
         self.left_bar.children = tuple([self.toolbar])
 
-    # def to_widget(self) -> Widget:
-    #     """
-    #     Convert the Matplotlib figure to a widget.
-    #     """
-    #     return VBox([
-    #         self.top_bar.to_widget(),
-    #         HBox([
-    #             self.left_bar.to_widget(), self._fig.canvas,
-    #             self.right_bar.to_widget()
-    #         ]),
-    #         self.bottom_bar.to_widget()
-    #     ])
-
     def home(self):
         self._autoscale()
         self.crop(**self._crop)
diff --git a/src/plopp/toolbar.py b/src/plopp/toolbar.py
index 4b8810d6..a8d45fdb 100644
--- a/src/plopp/toolbar.py
+++ b/src/plopp/toolbar.py
@@ -16,7 +16,6 @@ def __init__(self, callback: Callable = None, **kwargs):
         """
         Create a new button with a callback that is called when the button is clicked.
         """
-        from ipywidgets import Button
         self.widget = Button(**{**LAYOUT_STYLE, **kwargs})
         self._callback = callback
         self.widget.on_click(self)
@@ -34,7 +33,6 @@ def __init__(self, callback: Callable, value: bool = False, **kwargs):
         cases, we need to toggle the button color without triggering the callback
         function.
         """
-        # from ipywidgets import Button
         self.widget = Button(**{**LAYOUT_STYLE, **kwargs})
         self._callback = callback
         self.widget.on_click(self)
@@ -84,10 +82,3 @@ def __init__(self, tools=None):
             setattr(self, key, tool)
             self._widgets[key] = tool.widget
         super().__init__(tuple(self._widgets.values()))
-
-    # def to_widget(self):
-    #     """
-    #     Return the VBox container
-    #     """
-    #     from ipywidgets import VBox
-    #     return VBox(tuple(self._widgets.values()))
diff --git a/src/plopp/view.py b/src/plopp/view.py
index c69e3ec2..5048070d 100644
--- a/src/plopp/view.py
+++ b/src/plopp/view.py
@@ -17,7 +17,3 @@ def __init__(self, *nodes):
     @abstractmethod
     def notify_view(self, _):
         return
-
-    @abstractmethod
-    def to_widget(self):
-        return

From f2a25882be95eb326d52a9ef477e5e8f93804484 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@esss.se>
Date: Mon, 19 Sep 2022 12:59:40 +0200
Subject: [PATCH 06/10] flake8

---
 src/plopp/interactive.py   | 1 -
 src/plopp/toolbar.py       | 2 --
 src/plopp/widgets/slice.py | 1 -
 3 files changed, 4 deletions(-)

diff --git a/src/plopp/interactive.py b/src/plopp/interactive.py
index fd418b88..6680ea62 100644
--- a/src/plopp/interactive.py
+++ b/src/plopp/interactive.py
@@ -1,7 +1,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright (c) 2022 Scipp contributors (https://github.com/scipp)
 
-from .displayable import Displayable
 from .figure import Figure
 from .toolbar import Toolbar
 
diff --git a/src/plopp/toolbar.py b/src/plopp/toolbar.py
index a8d45fdb..410ec6a3 100644
--- a/src/plopp/toolbar.py
+++ b/src/plopp/toolbar.py
@@ -5,8 +5,6 @@
 from functools import partial
 from typing import Callable
 
-from .displayable import Displayable
-
 LAYOUT_STYLE = {"layout": {"width": "34px", "padding": "0px 0px 0px 0px"}}
 
 
diff --git a/src/plopp/widgets/slice.py b/src/plopp/widgets/slice.py
index 74e612ee..e4417b18 100644
--- a/src/plopp/widgets/slice.py
+++ b/src/plopp/widgets/slice.py
@@ -3,7 +3,6 @@
 
 from scipp import DataArray
 from ..tools import value_to_string
-from ..view import View
 from ..model import node
 
 import ipywidgets as ipw

From 4b4d44106b52c71c3eb5de7587980f3fe5ce0ae5 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@esss.se>
Date: Mon, 19 Sep 2022 13:37:36 +0200
Subject: [PATCH 07/10] watch -> _plopp_observe

---
 src/plopp/model.py              | 8 ++++----
 src/plopp/widgets/checkboxes.py | 6 +++++-
 src/plopp/widgets/slice.py      | 5 ++---
 3 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/plopp/model.py b/src/plopp/model.py
index 5dbebfe1..c585c101 100644
--- a/src/plopp/model.py
+++ b/src/plopp/model.py
@@ -56,10 +56,10 @@ def input_node(obj):
 
 def widget_node(widget):
     n = Node(func=lambda: widget.value)
-    # TODO: Our custom widgets have a 'watch' method instead of 'observe' because
-    # inheriting from VBox causes errors when overriding the 'observe' method
+    # TODO: Our custom widgets have a '_plopp_observe' method instead of 'observe'
+    # because inheriting from VBox causes errors when overriding the 'observe' method
     # (see https://bit.ly/3SggPVS).
-    # We need to be careful that widgets don't get a method named 'watch' in the future.
-    func = widget.watch if hasattr(widget, 'watch') else widget.observe
+    func = widget._plopp_observe if hasattr(widget,
+                                            '_plopp_observe') else widget.observe
     func(n.notify_children, names="value")
     return n
diff --git a/src/plopp/widgets/checkboxes.py b/src/plopp/widgets/checkboxes.py
index 274c4096..3658ca3b 100644
--- a/src/plopp/widgets/checkboxes.py
+++ b/src/plopp/widgets/checkboxes.py
@@ -41,7 +41,11 @@ def __init__(self, entries: list, description=""):
 
         super().__init__(to_hbox)
 
-    def watch(self, callback: Callable, **kwargs):
+    def _plopp_observe(self, callback: Callable, **kwargs):
+        """
+        TODO: Cannot name this method 'observe' when inheriting from HBox, so we name
+        it '_plopp_observe' instead (see https://bit.ly/3SggPVS).
+        """
         for chbx in self.checkboxes.values():
             chbx.observe(callback, **kwargs)
 
diff --git a/src/plopp/widgets/slice.py b/src/plopp/widgets/slice.py
index e4417b18..5c439607 100644
--- a/src/plopp/widgets/slice.py
+++ b/src/plopp/widgets/slice.py
@@ -61,11 +61,10 @@ def _update_label(self, change):
         coord = self.controls[dim]['coord'][dim, change['new']]
         self.controls[dim]['label'].value = _coord_to_string(coord)
 
-    def watch(self, callback: Callable, **kwargs):
+    def _plopp_observe(self, callback: Callable, **kwargs):
         """
         TODO: Cannot name this method 'observe' when inheriting from HBox, so we name
-        it 'watch' instead (see https://bit.ly/3SggPVS). We need to be careful that
-        widgets don't get a method named 'watch' in the future.
+        it '_plopp_observe' instead (see https://bit.ly/3SggPVS).
         """
         for dim in self.controls:
             self.controls[dim]['slider'].observe(callback, **kwargs)

From 99fcd006b87b880aa75899f2bc12804aa962ef79 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@esss.se>
Date: Mon, 19 Sep 2022 15:31:28 +0200
Subject: [PATCH 08/10] add extra underscore at the end of _plopp_observe

---
 src/plopp/model.py              | 4 ++--
 src/plopp/widgets/checkboxes.py | 6 +-----
 src/plopp/widgets/slice.py      | 6 +-----
 3 files changed, 4 insertions(+), 12 deletions(-)

diff --git a/src/plopp/model.py b/src/plopp/model.py
index c585c101..a7aeff29 100644
--- a/src/plopp/model.py
+++ b/src/plopp/model.py
@@ -59,7 +59,7 @@ def widget_node(widget):
     # TODO: Our custom widgets have a '_plopp_observe' method instead of 'observe'
     # because inheriting from VBox causes errors when overriding the 'observe' method
     # (see https://bit.ly/3SggPVS).
-    func = widget._plopp_observe if hasattr(widget,
-                                            '_plopp_observe') else widget.observe
+    func = widget._plopp_observe_ if hasattr(widget,
+                                             '_plopp_observe_') else widget.observe
     func(n.notify_children, names="value")
     return n
diff --git a/src/plopp/widgets/checkboxes.py b/src/plopp/widgets/checkboxes.py
index 3658ca3b..d9cd5b8a 100644
--- a/src/plopp/widgets/checkboxes.py
+++ b/src/plopp/widgets/checkboxes.py
@@ -41,11 +41,7 @@ def __init__(self, entries: list, description=""):
 
         super().__init__(to_hbox)
 
-    def _plopp_observe(self, callback: Callable, **kwargs):
-        """
-        TODO: Cannot name this method 'observe' when inheriting from HBox, so we name
-        it '_plopp_observe' instead (see https://bit.ly/3SggPVS).
-        """
+    def _plopp_observe_(self, callback: Callable, **kwargs):
         for chbx in self.checkboxes.values():
             chbx.observe(callback, **kwargs)
 
diff --git a/src/plopp/widgets/slice.py b/src/plopp/widgets/slice.py
index 0151b63d..f9a5119b 100644
--- a/src/plopp/widgets/slice.py
+++ b/src/plopp/widgets/slice.py
@@ -62,11 +62,7 @@ def _update_label(self, change):
         coord = self.controls[dim]['coord'][dim, change['new']]
         self.controls[dim]['label'].value = _coord_to_string(coord)
 
-    def _plopp_observe(self, callback: Callable, **kwargs):
-        """
-        TODO: Cannot name this method 'observe' when inheriting from HBox, so we name
-        it '_plopp_observe' instead (see https://bit.ly/3SggPVS).
-        """
+    def _plopp_observe_(self, callback: Callable, **kwargs):
         for dim in self.controls:
             self.controls[dim]['slider'].observe(callback, **kwargs)
 

From c99ef5bf25f0b10a731f2eee74b5c40ae46dcffa Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@esss.se>
Date: Mon, 19 Sep 2022 15:33:43 +0200
Subject: [PATCH 09/10] fix python tests

---
 tests/graph_nodes_test.py | 2 --
 1 file changed, 2 deletions(-)

diff --git a/tests/graph_nodes_test.py b/tests/graph_nodes_test.py
index 6719ac0f..24db98d7 100644
--- a/tests/graph_nodes_test.py
+++ b/tests/graph_nodes_test.py
@@ -117,7 +117,6 @@ def test_slice_3d_cube():
     w = widget_node(sl)
 
     slice_node = slice_dims(a, w)
-    sl.make_view(slice_node)
 
     fig = figure(slice_node)
     Plot([fig.to_widget(), sl])
@@ -131,7 +130,6 @@ def test_3d_image_slicer_with_connected_side_histograms():
     w = widget_node(sl)
 
     sliced = slice_dims(a, w)
-    sl.make_view(sliced)
     fig = figure(sliced)
 
     histx = node(sc.sum, dim='xx')(sliced)

From 9a161abad71d674ea8823b93f8f43abf49e6c952 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@esss.se>
Date: Mon, 19 Sep 2022 15:58:45 +0200
Subject: [PATCH 10/10] remove hard dependency on ipywidgets

---
 src/plopp/__init__.py         |  2 --
 src/plopp/plot.py             | 14 --------------
 src/plopp/widgets/__init__.py |  1 +
 src/plopp/widgets/box.py      | 20 ++++++++++++++++++++
 src/plopp/wrappers.py         |  9 ++++-----
 tests/graph_nodes_test.py     | 16 ++++++++--------
 6 files changed, 33 insertions(+), 29 deletions(-)
 delete mode 100644 src/plopp/plot.py
 create mode 100644 src/plopp/widgets/box.py

diff --git a/src/plopp/__init__.py b/src/plopp/__init__.py
index 131f1841..c7a3bd27 100644
--- a/src/plopp/__init__.py
+++ b/src/plopp/__init__.py
@@ -14,12 +14,10 @@
 plt.ioff()
 
 from .graph import show_graph
-from .plot import Plot
 from .model import Node, node, input_node, widget_node
 from .wrappers import plot, figure, slicer
 
 from . import data
-from . import widgets
 
 
 def patch_scipp():
diff --git a/src/plopp/plot.py b/src/plopp/plot.py
deleted file mode 100644
index d4b5bb9a..00000000
--- a/src/plopp/plot.py
+++ /dev/null
@@ -1,14 +0,0 @@
-# SPDX-License-Identifier: BSD-3-Clause
-# Copyright (c) 2022 Scipp contributors (https://github.com/scipp)
-
-from ipywidgets import VBox, HBox
-
-
-class Plot(VBox):
-
-    def __init__(self, views):
-        self.views = views
-        children = []
-        for view in self.views:
-            children.append(HBox(view) if isinstance(view, (list, tuple)) else view)
-        return super().__init__(children)
diff --git a/src/plopp/widgets/__init__.py b/src/plopp/widgets/__init__.py
index 1b8c87b4..c616efd2 100644
--- a/src/plopp/widgets/__init__.py
+++ b/src/plopp/widgets/__init__.py
@@ -4,5 +4,6 @@
 # flake8: noqa: F401
 
 # from .masks import MaskWidget, hide_masks
+from .box import Box
 from .checkboxes import Checkboxes
 from .slice import SliceWidget, slice_dims
diff --git a/src/plopp/widgets/box.py b/src/plopp/widgets/box.py
new file mode 100644
index 00000000..edc4e071
--- /dev/null
+++ b/src/plopp/widgets/box.py
@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright (c) 2022 Scipp contributors (https://github.com/scipp)
+
+from ipywidgets import VBox, HBox
+
+
+class Box(VBox):
+    """
+    Container widget that accepts a list of items. For each item in the list, if the
+    item is itself a list, it will be bade into a horizontal row of the underlying
+    items, if not, the item will span then entire row.
+    Finally, all the rows will be placed inside a vertical box container.
+    """
+
+    def __init__(self, widgets):
+        self.widgets = widgets
+        children = []
+        for view in self.widgets:
+            children.append(HBox(view) if isinstance(view, (list, tuple)) else view)
+        return super().__init__(children)
diff --git a/src/plopp/wrappers.py b/src/plopp/wrappers.py
index 6bee7427..488beb7f 100644
--- a/src/plopp/wrappers.py
+++ b/src/plopp/wrappers.py
@@ -3,7 +3,6 @@
 
 from .figure import Figure
 from .model import input_node, widget_node
-from .plot import Plot
 from .prep import preprocess
 
 from scipp import Variable, Dataset
@@ -120,7 +119,7 @@ def slicer(obj: Union[VariableLike, ndarray],
            keep: List[str] = None,
            *,
            crop: Dict[str, Dict[str, Variable]] = None,
-           **kwargs) -> Plot:
+           **kwargs):
     """
     Plot a multi-dimensional object by slicing one or more of the dimensions.
     This will produce one slider per sliced dimension, below the figure.
@@ -145,13 +144,13 @@ def slicer(obj: Union[VariableLike, ndarray],
     Returns
     -------
     :
-        A :class:`Plot` which will contain a :class:`Figure` and slider widgets.
+        A :class:`Box` which will contain a :class:`Figure` and slider widgets.
     """
     if not _is_interactive_backend():
         raise RuntimeError("The slicer can only be used with the interactive widget "
                            "backend. Use `%matplotlib widget` at the start of your "
                            "notebook.")
-    from plopp.widgets import SliceWidget, slice_dims
+    from plopp.widgets import SliceWidget, slice_dims, Box
     da = preprocess(obj, crop=crop, ignore_size=True)
     a = input_node(da)
 
@@ -161,4 +160,4 @@ def slicer(obj: Union[VariableLike, ndarray],
     w = widget_node(sl)
     slice_node = slice_dims(a, w)
     fig = figure(slice_node, **{**{'crop': crop}, **kwargs})
-    return Plot([fig, sl])
+    return Box([fig, sl])
diff --git a/tests/graph_nodes_test.py b/tests/graph_nodes_test.py
index 24db98d7..59fd047e 100644
--- a/tests/graph_nodes_test.py
+++ b/tests/graph_nodes_test.py
@@ -2,8 +2,8 @@
 # Copyright (c) 2022 Scipp contributors (https://github.com/scipp)
 
 import scipp as sc
-from plopp import Plot, figure, node, input_node, widget_node
-from plopp.widgets import Checkboxes, SliceWidget, slice_dims
+from plopp import figure, node, input_node, widget_node
+from plopp.widgets import Checkboxes, SliceWidget, slice_dims, Box
 from plopp.data import dense_data_array, dense_dataset
 import ipywidgets as ipw
 
@@ -60,7 +60,7 @@ def test_2d_image_smoothing_slider():
     smooth_node = node(gaussian_filter)(a, sigma=sigma_node)
 
     fig = figure(smooth_node)
-    Plot([fig.to_widget(), sl])
+    Box([fig.to_widget(), sl])
     sl.value = 5
 
 
@@ -76,7 +76,7 @@ def test_2d_image_with_masks():
 
     masks_node = hide_masks(a, w)
     fig = figure(masks_node)
-    Plot([fig.to_widget(), widget])
+    Box([fig.to_widget(), widget])
     widget.toggle_all_button.value = False
 
 
@@ -95,7 +95,7 @@ def test_two_1d_lines_with_masks():
     node_masks_a = hide_masks(a, w)
     node_masks_b = hide_masks(b, w)
     fig = figure(node_masks_a, node_masks_b)
-    Plot([fig.to_widget(), widget])
+    Box([fig.to_widget(), widget])
     widget.toggle_all_button.value = False
 
 
@@ -107,7 +107,7 @@ def test_node_sum_data_along_y():
 
     fig1 = figure(a)
     fig2 = figure(s)
-    Plot([[fig1.to_widget(), fig2.to_widget()]])
+    Box([[fig1.to_widget(), fig2.to_widget()]])
 
 
 def test_slice_3d_cube():
@@ -119,7 +119,7 @@ def test_slice_3d_cube():
     slice_node = slice_dims(a, w)
 
     fig = figure(slice_node)
-    Plot([fig.to_widget(), sl])
+    Box([fig.to_widget(), sl])
     sl.controls["zz"]["slider"].value = 10
 
 
@@ -137,5 +137,5 @@ def test_3d_image_slicer_with_connected_side_histograms():
 
     fx = figure(histx)
     fy = figure(histy)
-    Plot([[fx.to_widget(), fy.to_widget()], fig.to_widget(), sl])
+    Box([[fx.to_widget(), fy.to_widget()], fig.to_widget(), sl])
     sl.controls["zz"]["slider"].value = 10