Ignore the first question – I gave up completely on allowing multiple selections, as it ran into too many problems and the case where we might need more than one is purely theoretical, so I decided to keep it simple for now.
But the second issue needs solving if I’m going to have these filters at all. As I said, the problem can easily be seen on the tutorial video at timecode 11:05, so it’s not something unique to my code. If anyone else has implemented such a filter, how did you deal with get_field_object() failing when the result set is empty? This looks like a bug in get_field_object() to me.
