I am assuming you want the curtain wall to grow to meet the regular wall so it will be trapezoid in elevation.
In CW editing mode
Make environment visible so you can see the regular wall.
Have only the Scheme visible
Stretch the upper corner of the heavy frame until it hits the wall. The cursor will show the Perpendicular symbol when it does.
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"