Fixed a bug noticed on Mac with Qt5. On either Palette Editor Dilog or...

Fixed a bug noticed on Mac with Qt5.  On either Palette Editor Dilog or Overlay and Map Settings Dialog, selection of a Palette combo box resulted in containing no selected palette.  Problem was that the focus in event, used to ensure valid data on the dialog, was being issued during the pop-up of the combo box resulting in no selected palette.  Solution was to ignore focus events when the reason is Qt::PopupFocusReason.