Bug 21099: Reposition floating toolbars earlier

Bug 21099: Reposition floating toolbars earlier

To recreate:
- Go to the advanced search form
- scrolldown to position the toolbar on top of the window
- scrollup

https://screenshots.firefox.com/NnkFg3iOXqLPxfkd/pro.kohadev.org

The toolbar should have been repositioned earlier

Test plan:
Edit a patron
- scrolldown
- scrollup
- unfold the form in the header (tab "Search patrons", link "[+]")
- scrolldown
- scrollup
Advanced search
scrolldown
scrollup

You should notice the difference with and without this patch

Signed-off-by: Pierre-Luc Lapointe <pierreluc.lapointe@inLibro.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>