I think this issue is related to this plugin.
I set my interface language to French and switched to my test library in order to respond to a problem in the Viewer sub-forum.
I forgot to switch back to English before trying to use calibre, I wanted to switch to my Books library, so I tapped the context menu key, then right arrow, which resulted in this
The
Quick switch, Switch create library…, EpubSplit, and Quality Check options are disabled - as evidenced by missing icons .
When I switched back to English the
Quick switch option was restored, but
Switch create library…, EpubSplit, and Quality Check remain disabled:
In guess I'll have to completely remove Favourites and set it up again.
BR