LR secondary display?

[PeterAit]

My secondary display window is stuck in full screen mode. The Full Screen Mode menu option is not selected. Selecting it and turning it back off does not help. Ideas?

[mcbroomf]

Win or Mac?

I've not seen this problem but would do the following if affected;

1) Close LRC
    Disconnect 2nd monitor
    Open LRC and take a look at the 2nd mon icon (which should not there)
    Close LRC
    Reconnect monitor
    Open LRC and see if it still sees just one window (and then controls 2nd properly)
2) Disable graphics card if possible
3) Trash preferences