To change the height of the Transom/Head Gap or Door, click on the measurement field next to the Transom/Head Gap or the Door and enter the correct height.
Depending on your settings, one of these measurement fields will show as ''Auto'' - this means the height is getting automatically calculated based on the total height entered (A) and your default height setting for doors/transoms.
Once you specify the height for one of these, the software will auto-calculate the height of the remaining panel (Transom/Head Gap or Door).