You are responding to the new Tips & Tricks posting (for those wondering where this question came from).

A user has to open each task and select a tag to be assigned to it. (Other examples could be 'errand' or 'bill'.)

The "isRecurring" condition is looking at the whether the task has a "Repeat" timetable attached to it. (Repeat every month, repeat after 5 days are examples.).

In that post, she didn't want to include all of the repeating tasks in her list so she chose tag assignment approach to slice and dice the tasks as desired.

Hope this helps!

Oops. The condition is "isRepeating", not "isRecurring"

azclaire,

I've missed that "NOT tag:recur" is a tag (although it says right here: NOT...........T A G...........:recur).
Typical case of "can't see the forest for the trees".

Thanks for your help!