o.c.ui.menu.app: Explicitly add 'additions', 'group.editor' to Toolbar

.. because otherwise the tool bar gets messed up under E4. For E3, this
doesn't matter, but best keep the sources the same.

The branch name is wrong: This fixes #325, not 453.
Branch 453 had been closed, and was now re-created for this by accident.
Anyway, this fixes 325 while keeping the master and 4.x branch as similar as possible.