I've got some weird issue happening since I installed Windows 8.1 when it officially came out.
Every day, approximately within 10 minutes after boot of the system, the program (in all cases so far Mozilla Firefox) will switch by itself from window-filled mode to the desktop, so all I see is the desktop.
Then when I click on the icon again in the taskbar, it pops up again, but now snapped to the left (WIN key + Left key). Then I restore it again to window-filled mode.
I have absolutely no clue what is happening.