Bug 21139: Floating toolbar - Remove horizontal scrollbar on resize

Bug 21139: Floating toolbar - Remove horizontal scrollbar on resize

To test:
- add/edit a patron
- resize the window
=> Without this patch a horizontal scrollbar appears when resized
shorter

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit b5520f3e019f38cbd2ea75be0a13806f68a2f515)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
(cherry picked from commit 106ad2d6f01e6bdcf79b54791a437ae31746a059)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>