tdf#87944 COLOR-PICKER stays on wrong position.

After this patch dab2582f
under windows always open on the wrong position
(open in the middle of the application but not under the
pushbutton)

Change-Id: Ib245df6ccb2be768f7a12b638864d5c3cea1a390
Reviewed-on: https://gerrit.libreoffice.org/23557Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

vcl/win/window/salframe.cxx

@@ -1310,6 +1310,9 @@ void WinSalFrame::SetPosSize( long nX, long nY, long nWidth, long nHeight,
 
                 nX = aPt.x;
                 nY = aPt.y;
+
+                // the position is set
+                mbDefPos = false;
             }
     }