Mulled windows in Architecture Posted July 14, 2017 I can see how the cased opening could work. How do you get it to be represented correctly in the door & window schedule? So for example if the intent is two 2640 windows factory mulled together, you inset 2 windows and a cased opening. How do you represent this with one window call out and show the correct size and type in the window schedule? The schedule with recognize the record format for the two windows and the cased opening, so how do you represent all of this as a unit?