Yes, I finally checked documentation and found:
[quote]Accessing the Multiple Resources feature
The feature is only accessible in resources that contain Bible milestones; in general, this means Bibles, Bible Commentaries, original language fragments, etc. Add the Multiple Resources menu to a Bible by clicking the icon on the resource toolbar. The Multiple Resources option can be enabled and disabled after adding guest resources by clicking again, or by pressing Cmd+Shift+M (Mac) / Ctrl+Shift+M (Windows).
Logos Help (Bellingham, WA: Faithlife, 2018).
I suggest that the multiview icon be removed or disabled when the resource open does not contain Bible milestones. I just wasted time trying to get it to work on headwords for Bible dictionaries.
