The buttons on top of the page tree behave like a button group and
should be styled as such.

Resolves: #86916
Releases: master
Change-Id: I04e4f65cda19d6e1ed808ebdaecb942e21b202fa
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63915


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>