allow the gc to collect some objects after closing the dialog

gramps/plugins/tool/verify.py

@@ -752,6 +752,11 @@ def __init__(self, dbstate, uistate, track, glade, closeall):
         self.invert_button.connect("clicked", self.invert_clicked)
 
         self.parent_iter_cache = {}
+        self.track_ref_for_deletion("parent_iter_cache")
+        self.track_ref_for_deletion("real_model")
+        self.track_ref_for_deletion("filt_model")
+        self.track_ref_for_deletion("sort_model")
+        self.track_ref_for_deletion("warn_tree")
 
         self.real_model = Gtk.TreeStore(
             GObject.TYPE_BOOLEAN,
@@ -892,7 +897,7 @@ def close(self, *obj):
         """close the dialog and write out the file"""
         new_ignores = self.get_new_marking()
         self.save_ignored(new_ignores)
-
+        
         ManagedWindow.close(self, *obj)
         self.closeall()