One minor thing is that the "open status" default icon (an unchecked box) looks kind of like a unicode error when shown in context:

I don't know if that will bother anyone but me.

Also, how useful do you guys think min() and max() functions would be for priority? I'm inclined to wait for users to request them since they seem less clearly useful than open() and closed(), but if you'd definitely use them I can build them now.

For example, you could use min(normal) to select all tasks with priority normal or higher.

It's not something I would use day to day, but I could see its use in bigger companies (ones that highly customize priority levels).

I like min() and max() but wouldn't use them much here and can easily work around when I do.