Reproduction steps:
1. Create a new project
2. Toggle “Use new Hierarchy” setting (Edit > Preferences… > General)
3. Toggle “Use new Hierarchy” setting back to its previous state
4. Dock another window on top of the Hierarchy window so that the Hierarchy window becomes hidden
5. Observe the Console

Actual result: “Trying to access the DPI setting of a visual element that is not on a panel.” warnings are repeatedly thrown in the Console
Expected result: No errors or warnings are thrown

Reproducible with: 6000.6.0a5
Not reproducible with: 6000.3.15f1, 6000.4.7f1, 6000.5.0b8, 6000.6.0a4
Couldn’t reproduce with: 6000.0.75f1 (No new Hierarchy window)

Reproduced on: Windows 11, macOS Tahoe 26.4 (M4)

Note:
Full warning:
{code:java}
Trying to access the DPI setting of a visual element that is not on a panel.
UnityEngine.UIElements.AlignmentUtils:CeilToPanelPixelSize (UnityEngine.UIElements.VisualElement,single)
Unity.Hierarchy.HierarchyViewItem:Bind (Unity.Hierarchy.HierarchyNode&,Unity.Hierarchy.HierarchyView) (at /Users/bokken/build/output/unity/unity/Modules/Hierarchy/Managed/HierarchyViewItem.cs:215)
Unity.Hierarchy.HierarchyViewItemContainer:Bind (Unity.Hierarchy.HierarchyNode&,Unity.Hierarchy.HierarchyView) (at /Users/bokken/build/output/unity/unity/Modules/Hierarchy/Managed/HierarchyViewItemContainer.cs:68)
Unity.Hierarchy.HierarchyViewColumnName:BindCell (UnityEngine.UIElements.VisualElement,int) (at /Users/bokken/build/output/unity/unity/Modules/Hierarchy/Managed/HierarchyViewColumnName.cs:94)
UnityEngine.UIElements.HierarchyV2.CollectionView:RefreshItems ()
Unity.Hierarchy.Editor.HierarchyWindow:OnGameObjectIconModeChanged () (at /Users/bokken/build/output/unity/unity/Modules/HierarchyEditor/Managed/HierarchyWindow.cs:640)
UnityEditor.GUIView:ProcessEvent (UnityEngine.EntityId,intptr,bool&) (at /Users/bokken/build/output/unity/unity/Editor/Mono/GUIView.cs:70)
{code}