I didn't do it on purpose
- I suspect it's just the way the css you are using comes out. The position of the login window is determined by css, so depending on your exact configuration the position of the login bit might be on the left, or in the middle.
There were some changes to the basic underlying layouts - which will affect things, so this is probably a side effect of that.
The easiest way to see what's happening is to take a look at the css being applied using Firebug and then adjust accordingly.
Or post an example so we can take a look. (Or put the page online so we can see it from here.)
cheers
Bruce