         
         let isOpen = !(splitView.isSubviewCollapsed(subview))
         
-        var position = (isOpen ? 0 : lastWidth)
+        var position = (isOpen ? 0 : lastExtent)
         if (collapseRightward) {
             position = splitView.frame.size.width - position;
         }

        subview.removeConstraint(widthConstraint!)
        
        if isOpen {
            lastWidth = paneView.frame.size.width
        } else {
            subview.frame.size.width = 0
        }

        toggleSubview(self.leftView,
                      dividerIndex: 0,
                      paneView: sourceList.view,
                      lastExtent: &lastSourceWidth,
                      collapseRightward: false,
                      widthConstraint: sourceWidthConstraint)
    }
