if you right click on a part and click “cut”, either on purpose or on accident, the part will not re-appear when you press ctrl+z
how to recreate:
insert a part in Studio
Right click on the part
Click “Cut”
Press CTRL+Z
the part does not re-appear
pressing the play button and doing this used to crash studio, not sure if it still does, but that points to the bricks actually being a reference to memory, and the pointer being miss managed when it goes into the clipboard