Fix action states after subtitle cell editing cancelled

And successful editing too, just in case, even though it should result
in a registered action, which updates action states as well.

Closes #30

TODO.md

@@ -5,6 +5,8 @@ Gaupol 0.92/1.0
       frame-based or vice versa ([#28][])
 * [x] Fix error clicking undo or redo button dropdown arrow when no
       document is yet open ([#29][])
+* [x] Fix action states after subtitle cell editing cancelled ([#30][])
 
 [#28]: https://github.com/otsaloma/gaupol/issues/28
 [#29]: https://github.com/otsaloma/gaupol/issues/29
+[#30]: https://github.com/otsaloma/gaupol/issues/30

gaupol/agents/edit.py

@@ -334,12 +334,14 @@ def _on_view_renderer_edited(self, renderer, path, value, column):
             return page.project.set_duration(row, value)
         doc = page.text_column_to_document(col)
         page.project.set_text(row, doc, value)
+        self.update_gui()
 
     @aeidon.deco.export
     def _on_view_renderer_editing_canceled(self, *args):
         """Unset state set for editing cell."""
         self._set_unsafe_enabled(True)
         self.show_message(None)
+        self.update_gui()
 
     @aeidon.deco.export
     def _on_view_renderer_editing_started(self, renderer, editor, path, column):