Glade: Property 'Font name' of object class 'Font Button' is deprecated

Most of the deprecated issues were solved, but there’s one which has me confused. Glade (‘About glade’ doesn’t mention the version - but it’s fairly recent). On saving the project, in the details, I get:

Property 'Font name' of object class 'Font Button' is deprecated

I tried to leave the ‘Font name’ in the property editor empty, but that didn’t help. Google doesn’t seem to find that error message anywhere.

How can I avoid this warning? And avoid the ‘Save anyway?’ dialog?