         let optionsKey = NSEventModifierFlags(rawValue: theEvent!.modifierFlags.rawValue & NSEventModifierFlags.AlternateKeyMask.rawValue)
         let vertical = (optionsKey == .AlternateKeyMask)
         
-        if self.canAddSubview(vertical) == true {
+        if self.canAddSubview() == true {
             self.splitPaneView(pane, vertically: vertical)
         }
         else {

    }
    
    private func remove(paneView pane: PaneView) {
        let parentSplitView = pane.parentSplitView()
        if parentSplitView?.allSubPaneViews().count == 1 {
            parentSplitView?.removeFromSuperview()
        }
        else {
            pane.removeFromSuperview()
        }
    }
    
    func split(paneView pane: PaneView) {
        let mask = self.window?.styleMask;
        if (mask ==  NSFullScreenWindowMask || mask == NSFullSizeContentViewWindowMask) {
            NSBeep();

        }
        
        let newPaneView = PaneView.newPaneView()
        let newPaneViewIndex = self.indexOfPaneView(paneView)!+1
        
        let newSplitView = PressureSplitView()
        newSplitView.delegate = self.delegate
