I notice that the locations window now stays on top of the Ardour main window, and I don’t really like that. It used to drop behind it when I selected the main window. I prefer to select my location and then have the window stay open rather than frequently opening and closing it.
Feature requests go in tracker.ardour.org. Bugs and feature requests “reported” here will generally be ignored (or at least, forgotten).
Note that window layering (at least under Linux/X Window) tends to be very very very dependent on the window manager you use. Your experience may (or may not) be very different from other users. We try to code according to the Freedesktop standards for layering. Some window managers obey them, and some don’t.
Finally, we can’t provide options to cater to every possible desired behaviour. Stay-on-top vs. float-behind is contentious, but providing options to go back and forth for every windows gets absurd. You could, however, try
Windows > Theme Manager > all floating windows are dialogs to see if it helps.