Have you tried dragging the toolbar back with the ↔ cursor?
Keeping the EmEditor toolbar locations at bay is tricky. My recommendation is to set your toolbar locations for the window size you usually work with (e.g. maximised on your main screen) and then lock their locations.
In case you frequently hide and unhide toolbars: Set the locations with all toolbars shown, lock, then hide again.
Lock by right clicking a toolbar:
