add a tooltip to a setting
do not update icon workspace label if label not visible
if selection is empty we cannot show a menu
a few premature optimizations
scale down icons-behind-thumbnails and show them at their relative position
show an extended frame round the behind-the-icon-thumbnail, to visualize the monitor
new feature: (optionally) force new windows to open on primary monitor

if enabled, this will also force dialog windows to open on the same monitor as their parent