I'm not sure if this is a bug or I'm just failing to understand the logic behind it.
When I'm using the or block, after clicking the sprite, its size decreases by 10 pixels, but after the wait action it does not increase back to its original size
<img src="http://i297.photobucket.com/albums/mm206/KillerFromCro/notworking.jpg" border="0">
Using two different sub-events makes it work normally.
<img src="http://i297.photobucket.com/albums/mm206/KillerFromCro/working.jpg" border="0">
EDIT: tested by mouse click