UI Dialog not being positioned correctly

In 1.6rc2 dialogs where auto positioned quite well in the center of
the screen, now in 1.6rc5 all my dialogs are positioned too low on the
screen (way too low). I know I could "fix" this manually with an
offset but wanted to make sure I wasn't doing something wrong. Is
this a bug that is known, will it be fixed or is this now "expected"
behavior?