Okay I found my problem. It was an AJAX request in the ModXLight Manager Theme file login.html I just commented it out and had the submit button directly post the form... works fine for me.
So something isn’t working properly with the onComplete response...
I’m not sure why it was not working properly. I’m using Safari and FF3 on a Mac... in any case if anyone who is contributing bugs wants to file it (I don’t really know where to start nor do I have time right now).
The strange thing is that I’ve done fresh installs of 0.9.6.2 and haven’t had any issues. Is the default theme Light or Green? that could be the reason I haven’t seen it before if the default is not Light...