The advanced search dialog opens *behind* the main Recoll window (on my computer running Linux).
I use Linux. Perhaps this is not a problem on Microsof Windows.
I don't normally use this feature nor do I intend to use this feature. But, of course, other users might use this feature. I just checked "Start with advanced search dialog open"
and then restarted Recoll. When I did that, the advanced search dialog opened behind the main Recoll window. I suppose that the advanced search dialog should open in front of the main Recoll window. Right?