#722 "Undo" doesn't work sometimes

[Dustin Gunn]

Create a sprite, then resize it. In the properties window, click "make 1:1" and it will snap back to its original size. Press the undo button and NOTHING happens. The button stops responding until you click the layout window again, and even then, you CANNOT undo the 1:1 transformation.

Undo in general does not seem to work when you have the project window selected, which is not a very good idea.

Undo also doesn't let you undo image changes, which can be pretty crippling.