How to reproduce:
1. Create a new Unity project
2. In the Project window with the Two column layout, right-click on any folder in the folders list to open the context menu
3. Click “Show in Explorer”
4. Observe the Console
Expected result: There are no errors
Actual result: There are NullReferenceException errors
Reproducible with: 2023.2.0a15
Not reproducible with: 2020.3.48f1, 2021.3.25f1, 2022.2.20f1, 2023.1.0b16, 2023.2.0a14
Reproducible on: Windows 11 Pro
Full error:
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.IMGUI.Controls.TreeViewController.IterateVisibleItems (System.Int32 firstRow, System.Int32 numVisibleRows, System.Single rowWidth, System.Boolean hasFocus) (at <20f0cdc70d9c4530b7c0a934acf1310f>:0)
UnityEditor.IMGUI.Controls.TreeViewController.OnGUI (UnityEngine.Rect rect, System.Int32 keyboardControlID) (at <20f0cdc70d9c4530b7c0a934acf1310f>:0)
UnityEditor.SceneHierarchy.DoTreeView (System.Single searchPathHeight) (at <20f0cdc70d9c4530b7c0a934acf1310f>:0)
UnityEditor.SceneHierarchy.OnGUI (UnityEngine.Rect rect) (at <20f0cdc70d9c4530b7c0a934acf1310f>:0)
UnityEditor.SceneHierarchyWindow.DoSceneHierarchy () (at <20f0cdc70d9c4530b7c0a934acf1310f>:0)
UnityEditor.SceneHierarchyWindow.OnGUI () (at <20f0cdc70d9c4530b7c0a934acf1310f>:0)
UnityEditor.HostView.InvokeOnGUI (UnityEngine.Rect onGUIPosition) (at <20f0cdc70d9c4530b7c0a934acf1310f>:0)
UnityEditor.DockArea.DrawView (UnityEngine.Rect dockAreaRect) (at <20f0cdc70d9c4530b7c0a934acf1310f>:0)
UnityEditor.DockArea.OldOnGUI () (at <20f0cdc70d9c4530b7c0a934acf1310f>:0)
UnityEngine.UIElements.IMGUIContainer.DoOnGUI (UnityEngine.Event evt, UnityEngine.Matrix4x4 parentTransform, UnityEngine.Rect clippingRect, System.Boolean isComputingLayout, UnityEngine.Rect layoutSize, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <665556350bee4980b6948a46b77dca24>:0)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)