i am posting about a problem i have been having for quite some time, with windows 10 as well as 7. Its rather hard to explain, which could be the reason i came up empty on searching for it, so i'll start with an image:
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Sometimes, after closing a full screen application, windows ignores part of one of my screens. the window in that image is maximized. i could put it in windowed mode and drag it over this "dead" part without a problem. however i cannot drag icons there or select this space by leftclick-dragging. i can even see the mouse cursor.

on rebooting, the black part is gone. this becomes rather tiresome though, and i'd like to find out why this keeps happening.

so far i've tried:
- changing desktop resolution
- unplugging screen
- reorder screens in windows
- restarting desktop window manager
- starting and closing fullscreen applications

if anybody has any suggestions, i'd appreciate it