When ExtendedBorders are used then height of the form title is specified in the current skin. Otherwise, height of the title is received from the system.
So, title height is always different, how it can does not affect? I will check this situation more…
I'm not mean that title's heigth is not changed with ExtendedBorders on/off – it is changed, obviously. I'm mean that title's font is twice bigger then system one in both cases.