What am I doing wrong with PopUp and regular expression matching for URLs?

Hi! I'm trying to get a pop up to show on a specific PAGE on the site whose URL is in for form of:
http://site.com/models-draft/?B=Something

Regex like the following do not work (no pop up):
.*models.*
.*mo.*

While regex like the following DOES work, but are undesirable for because they are not restrictive enough:
.*m.*
.*o.*

Every regex tester that I have tried suggests that the two longer regex should work. What am I missing here?