{"category": "Unity Engine/Editor/Extensions", "keywords": "Unity, Editor, Find, Panel, rootVisualElement, Name"} Find panel's rootVisualElement by panel name.

FindPanelRootVisualElementByPanelName.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;
using UnityEngine.UIElements;

public static VisualElement FindPanelRootVisualElementByPanelName(string panelName)
{
    // UnityEngine.UIElements.UIElementsUtility.GetAllPanels
    // UnityEngine.UIElements.UIElementsUtility.GetPanelsIterator
    // UnityEngine.UIElements.Panel.name
    // UnityEngine.UIElements.Panel.visualTree.name
    BindingFlags bindingFlags = BindingFlags.Static | BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;
    Assembly assembly = typeof(VisualElement).Assembly;
    Type typeUieUtil = assembly.GetType("UnityEngine.UIElements.UIElementsUtility");
    MethodInfo miGetPanelsIter = typeUieUtil.GetMethod("GetPanelsIterator", bindingFlags);
    IEnumerator panelsIter = (IEnumerator)miGetPanelsIter.Invoke(null, null);
    Type typePanel = assembly.GetType("UnityEngine.UIElements.Panel");
    Type typeKvIntPanel = typeof(KeyValuePair<,>).MakeGenericType(typeof(int), typePanel);
    PropertyInfo piValue = typeKvIntPanel.GetProperty("Value");
    PropertyInfo piName = typePanel.GetProperty("name", bindingFlags);
    PropertyInfo piVisualTree = typePanel.GetProperty("visualTree", bindingFlags);
    while (panelsIter.MoveNext())
    {
        object kvIntPanel = panelsIter.Current;
        object currPanelObj = piValue.GetValue(kvIntPanel, null);
        string currPanelName = (string)piName.GetValue(currPanelObj, null);
        VisualElement visualTree = null;
        if (string.IsNullOrEmpty(currPanelName))
        {
            visualTree = (VisualElement)piVisualTree.GetValue(currPanelObj, null);
            currPanelName = visualTree.name;
        }

        if (currPanelName == panelName)
        {
            visualTree ??= (VisualElement)piVisualTree.GetValue(currPanelObj, null);
            return visualTree;
        }
    }

    return null;
}