Please describe the problem:
Try this.

Steps to reproduce:
1. go to about:blank, or an address of your choice.
2. type in the address of a resource that requires WWW-Authentication
3. wait for the prompt to appear


Actual results:
URL changes back to previous address.

Expected results:
URL does not change.

Does this happen every time?
Yes.

Other information:
I notice how the address does not change until the page has started displaying.
I think that if the address changed when being prompted for a password, too,
this problem would hide away as a result, but I do think there is some broken
flow logic in there somewhere.

Cheers!