Open LyX window disables mouse clicks everywhere else

I have a strange issue. Whenever I open a LyX file, say, on half a screen, my left/right mouse clicks only register at the LyX window: they do not work on the other half or on the taskbar, and only resume working when I manually minimize the LyX window. The middle mouse button does work outside the LyX window though.

Has anyone encountered such an issue?