First off thanks for your help.
I've been trying to play with the properties of the button to do that but I'm facing a problem (again :þ )
When I hit F1 the button is pressed, the tiles disappear and then reappear as planned, then the button switches to off, then to on, and nothing happens.
Here's a screenshot of my button properties :
What I'd like to accomplish is to have the tiles appear for 1,5 seconds then disappear for 1,5 seconds and etc...
I surely must have done something wrong but I can't find what, and the F8 help didn't really help me cause I don't have the same categories as the ones listed.