From Windows 7, there is a function called Aero snap enabled as default.
This is a function where in desktop, when you move Window to edge of the screen, Window automatically resizes to fill screen, and restores original size when moved away from edge.
This is useful once you get used to it, but in some case this is unwanted.
To disable, press “Win + X” to open power menu, click Control Panel. (or call control panel from settings charm)
In Control Panel, click “Ease of Access”
Under “Ease of Access Center”, click “Change how your mouse works”
Under “Make it easier to manage windows”, check “Prevent windows from being automatically arranged when moved to the edge of the screen”.
Now, window will not resize when you move to edge of the screen.
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