Created attachment 40423 [details]
Libreoffice Writer toolbar screenshot
The toolbar can actually be removed, but after closing LibreOffice and opening it again, the toolbar is back.
See screenshot in attachment. The recurring toolbar is the empty one left of the mouse cursor.
This bug was originally reported in ArchLinux bug tracker, here:
This really is an archlinux bug and not a libreoffice bug. The blank toolbar is caused by a former ( 'ooo-build' ) feature which archlinux is obviously shipping. Lets leave the archlinux bug track this. The good news is that I recently fixed this problem and the archlinux maintainer more than likely will pick up the changes for the next release ( and may even have already done that ). for reference.
where  is the fix on the master branch and  the fix on the release branch
Thanks for the quick solution!
This is a Writer issue (indeed, it just looks line one, see comment #1), therefore changed the 'Component' field accordingly.