Keep both NSSplitViewController's child controllers in first responder chain

Question

I\'ve a document based app with an NSSplitViewController as the main window\'s content view controller. The left pane contains a custom view with controller, which implement

Answer 1

In Swift 4 you can do the following:

override func supplementalTarget(forAction action: Selector, sender: Any?) -> Any? {
    for childViewController in childViewControllers {
        if childViewController.responds(to: action) {

            return childViewController
        } else {
            guard let supplementalTarget = childViewController.supplementalTarget(forAction: action, sender: sender) else {
                continue
            }

            return supplementalTarget
        }
    }

    return super.supplementalTarget(forAction: action, sender: sender)
}

Answer 2

Connect to First Responder.

You can have all child view controllers respond to actions by implementing -[NSResponder supplementalTargetForAction:sender:] in your NSSplitViewController subclass:

- (id)supplementalTargetForAction:(SEL)action sender:(id)sender
{
    id target = [super supplementalTargetForAction:action sender:sender];

    if (target != nil) {
        return target;
    }

    for (NSViewController *childViewController in self.childViewControllers) {
        target = [NSApp targetForAction:action to:childViewController from:sender];

        if (![target respondsToSelector:action]) {
            target = [target supplementalTargetForAction:action sender:sender];
        }

        if ([target respondsToSelector:action]) {
            return target;
        }
    }

    return nil;
}