Tabs inside Musescore program gone ?

I use Musescore mainly for my guitar students. I would quite often have four or five songs open within Musescore at the same time, each selectable by tabs within the program.
It seems I can no longer have various scores open with tabs within Musescore?
In V.4 it seems each score creates a new tab in Windows bottom toolbar.
Is there a preference setting for this? or is it that just the way it is?