All scrollers get sticky - and I need to reboot!

Every now and then, all the scrollers of any application suddenly become
sticky.

That is, if I try to drag the scroller down or click below it, instead of
paging or scrolling downwards in the window, the scroller jumps back to the
top and I just cannot see what's below the current visible area!

I'm not even able to key down. As soon as I reach the bottom of the visible
area, I'm not able to move my cursor downwards any further.

Is this a known bug??


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