diff --git a/src/haz3lcore/zipper/Editor.re b/src/haz3lcore/zipper/Editor.re
index b6b30f65bc..4840335ad9 100644
--- a/src/haz3lcore/zipper/Editor.re
+++ b/src/haz3lcore/zipper/Editor.re
@@ -238,4 +238,7 @@ let get_projector = (id: Id.t, ed: t) =>
   Projector.Map.find(id, ed.state.zipper.projectors);
 
 let add_projector = (id: Id.t, p: Projector.t, ed: t) =>
-  update_z(_ => Zipper.add_projector(id, p, ed.state.zipper), ed);
+  update_z(
+    z => {...z, projectors: Projector.Map.add(id, p, z.projectors)},
+    ed,
+  );
diff --git a/src/haz3lcore/zipper/Projector.re b/src/haz3lcore/zipper/Projector.re
index ed8475706f..eaac774a2e 100644
--- a/src/haz3lcore/zipper/Projector.re
+++ b/src/haz3lcore/zipper/Projector.re
@@ -174,7 +174,7 @@ let guy_of_rev = (id, t, (start, last)) => {
   last_id: Piece.id(start),
 };
 let proj_info = (term_ranges, id: Id.t, t: t, acc: start_map) => {
-  print_endline("proj_info for id: " ++ Id.to_string(id));
+  //print_endline("proj_info for id: " ++ Id.to_string(id));
   switch (Id.Map.find_opt(id, term_ranges)) {
   | Some(range) =>
     let guy = guy_of(id, t, range);
@@ -185,7 +185,7 @@ let proj_info = (term_ranges, id: Id.t, t: t, acc: start_map) => {
   };
 };
 let proj_info_rev = (term_ranges, id: Id.t, t: t, acc: start_map) => {
-  print_endline("proj_info for id: " ++ Id.to_string(id));
+  // print_endline("proj_info for id: " ++ Id.to_string(id));
   switch (Id.Map.find_opt(id, term_ranges)) {
   | Some(range) =>
     let guy = guy_of(id, t, range);
diff --git a/src/haz3lcore/zipper/Zipper.re b/src/haz3lcore/zipper/Zipper.re
index f229d4f454..39333be17a 100644
--- a/src/haz3lcore/zipper/Zipper.re
+++ b/src/haz3lcore/zipper/Zipper.re
@@ -30,16 +30,6 @@ type t = {
   projectors: Projector.Map.t,
 };
 
-let get_projectors = (z: t): Projector.Map.t => z.projectors;
-
-let get_projector = (id: Id.t, z: t): option(Projector.t) =>
-  Projector.Map.find(id, z.projectors);
-
-let add_projector = (id: Id.t, p: Projector.t, z: t): t => {
-  ...z,
-  projectors: Projector.Map.add(id, p, z.projectors),
-};
-
 let init: unit => t =
   () => {
     selection: Selection.mk([]),
diff --git a/src/haz3lcore/zipper/action/Move.re b/src/haz3lcore/zipper/action/Move.re
index 3b75437a8a..441df3a943 100644
--- a/src/haz3lcore/zipper/action/Move.re
+++ b/src/haz3lcore/zipper/action/Move.re
@@ -6,7 +6,7 @@ open Sexplib.Std;
 [@deriving (show({with_path: false}), sexp, yojson)]
 type movability =
   | CanEnter(int, int)
-  | SkipTo(Id.t)
+  | SkipTo(ProjectorAction.thing)
   | CanPass
   | CantEven;
 
diff --git a/src/haz3lcore/zipper/action/ProjectorAction.re b/src/haz3lcore/zipper/action/ProjectorAction.re
index 0736c7228d..599733b208 100644
--- a/src/haz3lcore/zipper/action/ProjectorAction.re
+++ b/src/haz3lcore/zipper/action/ProjectorAction.re
@@ -2,29 +2,53 @@ open Zipper;
 open Util;
 //open OptUtil.Syntax;
 
-let get_id_before = (seg, ancestors, projectors) =>
+[@deriving (show({with_path: false}), sexp, yojson)]
+type relation =
+  | Parent
+  | Sibling;
+
+[@deriving (show({with_path: false}), sexp, yojson)]
+type thing = {
+  id: Id.t,
+  relation,
+};
+
+let get_id_before = (seg, ancestors, projectors): option(thing) =>
   switch (Projector.split_seg(seg, projectors)) {
-  | Some(([_, ..._] as xs, _, _, _)) => Piece.id(ListUtil.last(xs))
+  | Some(([_, ..._] as xs, _, _, _)) =>
+    Some({id: Piece.id(ListUtil.last(xs)), relation: Sibling})
   | Some(([], _, _, _)) =>
     switch (Ancestors.parent(ancestors)) {
     | Some(a) =>
       print_endline("prev_id: empty pre using parent");
-      a.id;
+      print_endline("parent id: " ++ Id.show(a.id));
+      Some({id: a.id, relation: Parent});
     | None =>
       print_endline("prev_id: empty pre no ancestor");
-      Id.invalid; //TODO(andrew)
+      None; //TODO(andrew) //Id.invalid;
     }
   | None =>
     print_endline("prev_id: None");
-    Id.invalid; //TODO(andrew)
+    None; //TODO(andrew) //Id.invalid;
   };
 
-let get_id_after = (seg, projectors) =>
+let get_id_after = (seg, ancestors, projectors): option(thing) =>
   switch (Projector.split_seg(seg, projectors)) {
-  | Some((_, _, [hd, ..._], _)) => Piece.id(hd)
-  | _ =>
+  | Some((_, _, [hd, ..._], _)) =>
+    Some({id: Piece.id(hd), relation: Sibling})
+  | Some((_, _, [], _)) =>
+    switch (Ancestors.parent(ancestors)) {
+    | Some(a) =>
+      print_endline("next_id: empty pre using parent");
+      print_endline("parent id: " ++ Id.show(a.id));
+      Some({id: a.id, relation: Parent});
+    | None =>
+      print_endline("next_id: empty pre no ancestor");
+      None; //TODO(andrew) //Id.invalid;
+    }
+  | None =>
     print_endline("next_id: empty post");
-    Id.invalid; //TODO(andrew)
+    None; //TODO(andrew) //Id.invalid;
   };
 
 let neighbor_is =
@@ -33,58 +57,64 @@ let neighbor_is =
       last_map: Projector.start_map,
       {relatives: {siblings, ancestors}, projectors, _}: t,
     )
-    : (option(Id.t), option(Id.t)) => {
+    : (option(thing), option(thing)) => {
   let (l_nhbr, r_nhbr) = Siblings.neighbors(siblings);
   let seg = (siblings |> fst) @ (siblings |> snd);
   let l =
     switch (l_nhbr) {
     | Some(p) when Projector.Map.mem(Piece.id(p), last_map) =>
-      Some(get_id_before(seg, ancestors, projectors))
+      get_id_before(seg, ancestors, projectors)
     | _ => None
     };
   let r =
     switch (r_nhbr) {
     | Some(p) when Projector.Map.mem(Piece.id(p), start_map) =>
-      Some(get_id_after(seg, projectors))
+      get_id_after(seg, ancestors, projectors)
     | _ => None
     };
   (l, r);
 };
 
-let is_right_of = (id: Id.t, z) =>
+let id_right_of_z = (id: Id.t, z) =>
   switch (z.relatives.siblings, z.relatives.ancestors) {
   | ((_, [r, ..._]), _) => Piece.id(r) == id
   | ((_, []), []) => true // end of program
   | ((_, []), _) => false
   };
 
-let is_left_of = (id: Id.t, z) =>
+let id_left_of_z = (id: Id.t, z) =>
   switch (z.relatives.siblings, z.relatives.ancestors) {
   | (([_, ..._] as ls, _), _) => Piece.id(ListUtil.last(ls)) == id
   | (([], _), []) => true // beginning of program
   | (([], _), _) => false
   };
 
-let is_on = (d: Direction.t, id: Id.t) =>
+let id_on = (d: Direction.t, id: Id.t) =>
   switch (d) {
-  | Left => is_left_of(id)
-  | Right => is_right_of(id)
+  | Left => id_left_of_z(id)
+  | Right => id_right_of_z(id)
+  };
+
+let d2 = (relation, d) =>
+  switch (relation) {
+  | Sibling => d
+  | Parent => Direction.toggle(d)
   };
 
-let skip_to = (d: Direction.t, id, z) => {
+let skip_to = (d: Direction.t, {id, relation}, z) => {
   // print_endline("ProjectorAction.skip_to");
   Zipper.do_until(
     Zipper.move(d),
-    is_on(d, id),
+    id_on(d2(relation, d), id),
     z,
   );
 };
 
-let skip_select_to = (d: Direction.t, id, z) => {
+let skip_select_to = (d: Direction.t, {id, relation}, z) => {
   // print_endline("ProjectorAction.skip_select_to");
   Zipper.do_until(
     Zipper.select_caret(d),
-    is_on(d, id),
+    id_on(d2(relation, d), id),
     z,
   );
 };
diff --git a/src/haz3lweb/view/Deco.re b/src/haz3lweb/view/Deco.re
index 92fc01c3e3..86715ad6d8 100644
--- a/src/haz3lweb/view/Deco.re
+++ b/src/haz3lweb/view/Deco.re
@@ -68,9 +68,10 @@ module Deco =
         }
       ) {
       | _ =>
+        print_endline("PROJECTOR CRASH: sel_of_piece");
         //TODO(andrew): relax. this is the case when tiles are missing
         //measured info due to being hidden by a projector
-        []
+        [];
       };
     let start_shape =
       switch (Piece.nibs(p)) {
@@ -350,7 +351,11 @@ module Deco =
     List.concat([
       //[Node.div(~attr=Attr.id("caret"), [])],
       caret(zipper),
-      indication_deco(zipper),
+      try(indication_deco(zipper)) {
+      | _ =>
+        print_endline("PROJECTOR CRASH: indication_deco");
+        [];
+      },
       selected_pieces(zipper),
       backpack(zipper),
       targets'(zipper.backpack, sel_seg),