Looks like Microsoft is still tweaking their UI quite a bit with the latest changes continuing to be seen at TechEd 2010.
Now these aren't huge changes, but it does show Microsoft is paying attention to detail, which is something that will be important if the masses are to adopt this phone.
Long Zheng noticed how the old icons in the common application bar had no text to identify them, making it a bit harder for the user to adapt to them since they could be changed by developer willy-nilly. Now, however, when you expand the bar by swiping up, it reveals more details including the icon names.
Once again, nothing huge, just nice to know Microsoft is looking out for perfection this time around.