When a single view is active, the other views are not selectable in the tabs located on the lower left of the frame. Only perspective remains highlighted (even if another view is active). I have to go back to the 4–pane config to select a different view.
Is there an option that invokes this type of behavior? I’m pretty sure this was working the first time I tried it.
OK - good! I’ve had this happen - not this specific thing but one thing or another just stop working for no apparent reason, and a restart clears the cobwebs.