Hi Steve,
I can't say I've ever seen the Storyline ribbon become minimized - so how it would happen is a bit of a mystery to me. Did you happen to grab a screenshot of this before it came back? Often a reboot of Storyline or your system is a good solution as it just gives everything a reset.
I haven't seen this in Storyline - although within Presenter you'll sometimes lose access to the ribbon and that typically involves a repair of the software. If you see it again (I hope not) can you take a screenshot and share it with us here?