ChangeEvent behaviour, bug or design choice?

Unity Engine
1

Hi
I have a Foldout that has a Toggle child down its ContentContainer hierarchy.

Now when I register a ChangeEvent callback to foldout it is raised not only when I click on a foldout but also when I click on the previously mentioned toggle.

It is a bug? I filed a bug report but got no response.

        var root = rootVisualElement;
        var foldout = new Foldout();
        foldout.RegisterValueChangedCallback(e=>Debug.Log("Change"));
       
        var toggle = new Toggle();
        foldout.Add(toggle);
        root.Add(foldout);
2

Yes, this seems like a bug. We got the report that you filed, thank you!

3

ChangeEvent that are sent to an element will propagate up the tree. In this case, the toggle change event bubbles up to the foldout. I agree that this behavior is not what’s expected in that case. Until we fix this, you can change your code to:

foldout.RegisterValueChangedCallback(e=> if(e.target == foldout) Debug.Log("Change"));