Steps to reproduce:

Use firefox (i'm on 21)
download drupal core (7.22)
download omega (3.1)
enable omega
go to /admin/appearance/settings/omega

unresponsive script warning.

Comments

This seems to be only FF.
I have the same set up on my local (Mac OS10.8), and found this post because I'm having the same issue. I didn't realize that's all that's needed though.
Neither Chrome 27 nor Safari 6 have this problem. Maybe it's not even a Drupal issue?

When you debug it, jquery has to parse some loop of 2000 different input fields to attach a behavior. Its certainly suboptimal behavior if nothing else.

dupe

Issue summary:View changes
Status:Active» Closed (cannot reproduce)

doenst happen on latest version of FF.