MAP Tab; Unable to Create Filter Bookmarks

In inreach.garmin.com, MAP tab, I cannot ADD a filter bookmark definition in the past week or so. I can define date range and message types, but when I press the + button to name a bookmark based on the filters, the entire window is masked by a black/gray overlay, and I can see the dialog box through the mask to name the bookmark. However if I click anywhere on the screen, the mask and the dialog box goes away.

I'm not sure how to describe this very clearly--if you've encountered it, you'll know exactly what I mean. Using Mac, Safari 11.0.2 (also tried firefox & chrome with same results).

I've done the forum search and couldn't find any similar issues there or in support. Apologies in advance if I missed something.

Suggestions?