By default, curtain walls attach to the face of adjoining walls. Use the shape handle to separate a curtain wall join from other curtain walls or exterior and interior walls. This allows more control over curtain wall joins and mullion placement to ensure proper design intent.
Default curtain wall installation to the face of a joined wall
To separate the join, select the curtain wall join shape handle; press Tab and watch the status bar to be sure you have selected the handle. Drag the handle to separate the curtain wall from the adjoining wall. This does not break the join between the 2 walls.
Curtain wall shape handle selected for dragging
Tip: You can achieve the same effect by using the Align tool to align the edge of the curtain wall with the center or edge of the joined wall. See Aligning Elements.