ok there's hidden code for YCTP in this image, which you have to type in there to unlock it. that it. the window breaking variant ain't gonna unlock this mode

Lastly, here's another 3 suggestions to Level Editor:
1. Add "Erase" button. Pressing it, will remove some objects and tile when selected. I know that Undo button exists, but it removes previous object, not the selected tile.
2. Add lunch tables. THIS is what my cafeteria looks like in this editor:

3. Some items (like Alarm Clock, Super BSODA and others) is missing in this editor. Maybe you should add them in there
I have some suggestions for the level editor, because I think it looks a bit bad.
Editor suggestions:
Non-editor suggestions:
I'm not forcing you to do all of these, but I think it would be easy to add, change or tweak some of the things I've suggested.