In Ext 2.2.1 the email-validator was changed a little bit to fix hanging browsers. (As explained in the changelog)

Unfortunatly this also broke validation for some valid emails. All emails containting a dash (-) are now not validated as correct email addresses.

You can easily check this behaviour in the form example page:
http://extjs.com/deploy/dev/examples/form/dynamic.html

Enter the valid address: test.test@example.com - all ok
Enter the valid address: test-test@example.com - not validated as correct email.

You can check in an example of Ext 2.2 the email test-test@example.com correctly passes validation.

I tried to fix the bug myself changing the regular expression and undoing one of the added slashes of the change from 2.2 to 2.2.1, but that did not fix the Bug. I'm also not a RegExp guru, and don't know which bugs in browser where corrected by the change introduced in 2.2.1.
Could anybody provide a fixed RegExp?