Note Inspector grayed out
 

OG 5.1b3.

I work on a document, adding data keys and values to some elements. I go away and come back, and the Note inspector is all grayed out--I can't edit anything.

Logging out/in seems to fix the problem temporarily.

What the?

It's a known issue, and will be fixed for the upcoming beta 4 release. In short, if you launch OmniGraffle with the Note Inspector showing, it won't work