Steps to reproduce:
1. Import and run the attached project
2. Double click on the item in the grid to show the dropdown.
3. Click on the dropdown to open it.
4. Press Ctrl+W.
5.Click anywhere on stage.
Actual result: the save() method of the GridItemEditor is called long after the grid has been removed from stage.
Desired result: when the grid is removed from stage, the item editing session is closed.