when you have a dock tabbed at the bottom or on the same edge as you taskbar (my task bar is on the bottom there might be a difference) there is this odd glitch that occurs (i'll see if i can get video of it latter cause i have to restart to get rid of the bug)
so to recreate this bug do the following:
1. make sure object dock is open
2. put a dock tabbed on the bottom and hide it
3. launch a fullscreen program
4. close the fullscreen program
5. open a maximized window
6. with the maximized window open try clicking in the area of the maximized window
if it work (recreating the bug) then it will set the maximized window to a non active window (there are 2 ways to tell if you window is unactive look on the bar at the top of that window, or by looking at the taskbar)
this is real annoying cause after i close a fullscreen program and go to skype the chat box is at the bottom and when i try click it its in the same area as the dock so it deselects the skype window.