I have seen similar bug in probably all versions since XP, not sure about 10 though. Sometimes a hover-tooltip would not disappear after moving mouse out of tas

I have seen similar bug in probably all versions since XP, not sure about 10 though. Sometimes a hover-tooltip would not disappear after moving mouse out of taskbar or system tray item. As I am using beefier hardware it gets more difficult to reproduce, but the general pattern is oversaturating I/O: have multiple memory hungry applications swapped out and try to bring them all back.