When two or more tabs rows exist and you select tab in the top row this row goes to the bottom. Standard behavior, but confusing nevertheless. Not anymore! The rows are not affected by selection now:
Interesting side effect of this change is that when tab is selected and mouse is over it, tab’s background is a mix of white and blue colors on Vista:
Standard behavior is a white tab’s background in this case, but I don’t know yet how to achieve this with controls library I use. Accidental mix of white and blue colors is interesting, so I’m leaving it as it is for now.