Resolved (figured it out) VisualElement code runs even though its parent GameObject is disabled

I created two GameObjects, each containing another UI document.
I disabled one of the GameObjects, UIPickCardColumn, so i can see only the enabled one.

It looks like the code in UIPickCardColumn still runs though (which i don't agree with but who am i to say that), and also has its VisualElements set to null.
UIPickCardColumn contains a single custom VisualElement at the root, PickCardColumn.
Its code is:

Code (CSharp):

1. using UnityEngine;
2. using UnityEngine.UIElements;
3.  
4. public class PickCardColumn : VisualElement
5. {
6.     public new class UxmlFactory : UxmlFactory<PickCardColumn, UxmlTraits> { }
7.     public PickCardColumn()
8.     {
9.         this.RegisterCallback<GeometryChangedEvent>(OnGeometryChange);
10.     }
11.     void OnGeometryChange(GeometryChangedEvent evt)
12.     {
13.         // test query
14.         VisualElement ve = this.Query($"ColumnPicker0");
15.         Debug.Log(ve);
16.         ve.style.display = DisplayStyle.Flex;
17.         this.UnregisterCallback<GeometryChangedEvent>(OnGeometryChange);
18.     }
19. }

Console output:


Note how the VisualElement "ColumnPicker0" is set to null.

When i enable the other UI Document, everything works fine, and the VisualElement is not null, so i assume the issue is not a typo in the code.

Console output:

 

The issue was that in UIBuilder, the wrong custom VisualElement was placed in the UI document UIPhasePlayCards. It contained the same VisualElement as UIPickCardColumn. I couldn't tell it was the wrong one because i renamed it to the name of the correct one in UIBuilder. I couldn't find way in UI Builder to find out which .cs file a visual element is defined in, besides its name, which can be changed.