Rectangle within a rectangle

[drafter]

Suppose you want to draw a rectangle (top view) within a wall to represent an opening. The tool will snap to the width of the wall. You only want to change the "X" dimension. How do you enter the info without typing the snapped dimension as well?

[Dave R]

If it's the X dimension you need but you've snapped the Y dimension, type the X dimension followed by a comma. i.e. 12, and hit Enter. If you snap the X dimension and need to enter the Y dimension, type the comma first, i.e. ,37.625 and hit Enter.