[medmonds]

After working in a file for a few hours, a couple times now the render tab has gotten stuck "greyed out", similar to what happens when you have a perspective camera view selected.
It is always fixable by exiting the file and re-opening it.

Just FYI. This happen to anyone else?

[raduc]

Just FYI. This happen to anyone else?

It happened to me when revit got stuck in one of the modify modes after editing families in place for instance. Next time it happens, try to press the Esc key 1 or 2 times.

[medmonds]

That makes sense in my case because I was doing in-place family editing around the time it happened.
Thanks!