         toggleSubview(self.rightView,
                       dividerIndex: 1,
                       paneView: infoPane.view,
-                      lastWidth: &lastInfoWidth,
+                      lastExtent: &lastInfoWidth,
                       collapseRightward: true,
                       widthConstraint: infoWidthConstraint)
     }

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

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