Indeed the Scanner pane (and other panes) can float around, but unfortunately I did not manage to detach it as a separate window from the Airspy program (tested now with ver 1784).
So currently I must have the Airspy program open somewhere and in the foreground for the Scanner pane to also be in the foreground.
If I click on a part of a window that is not related to Airspy, the Airspy (and Scanner) go to the background, unfortunately.
In the original version of the Scanner plugin, the Scanner pane was considered a separate window in addition to SDR# and stayed in the foreground while SDR# was minimized, and thus I could have continued using my laptop normally while viewing only the Scanner pane. (See another pic for example from the original Scanner plugin and the two separate windows.)
But this is I guess not related to the new and updated Scanner plugin, and it is more a "feature" of the non-stop-updating Airspy program.