I had no grammars, at least no grammars that the Exegetical Guide would look in. The "Grammars" section was always grey. So, after watching John Fidel's new video on his favorite layout, I decided to buy the two grammars that showed up in his example. After downloading them and restarting Logos and reindexing and all that, I noticed that "Grammars" was still grey in my Exegetical Guide.

I clicked in the reference box and clicked on on the right-arrow to the right of the passage reference, thinking I could force Logos to refresh the guide this way, but nothing changed. Only when I went to a different Bible verse did the Grammars section finally get un-greyed.
Expect: Addition of new resources to force a refresh of any guides that would be affected by their being there.