Steps to reproduce:

1. Create a project using the Universal 2D template
2. Go to "Window" -> "2D" -> "Tile Palette"
3. In the "Tile Palette" window, find the "Default Brush" drop-down
4. Select the "GameObject Brush" item from the list
5. Expand the "SceneRoot Grid" section
6. Go to "Unity" -> "Settings" ->"General" -> "Editor Theme"
7. Change from "Light" to "Dark" or vice versa

Actual results: Console displays an error

Expected results: No errors in the Console view

Reproducible with versions: 6000.0.63f1, 6000.2.15f1, 6000.3.1f1, 6000.4.0a5, 6000.5.0a3

Tested on (OS): macOS - Tahoe 26.1

Notes: Full error
{code:java}
SerializedObjectNotCreatableException: Object at index 0 is null
UnityEditor.Editor.CreateSerializedObject () (at /Users/bokken/build/output/unity/unity/Editor/Mono/Inspector/Editor.cs:717)
UnityEditor.Editor.GetSerializedObjectInternal () (at /Users/bokken/build/output/unity/unity/Editor/Mono/Inspector/Editor.cs:689)
UnityEditor.Editor.get_serializedObject () (at /Users/bokken/build/output/unity/unity/Editor/Mono/Inspector/Editor.cs:583)
UnityEditor.GridEditor.OnEnable () (at /Users/bokken/build/output/unity/unity/Modules/GridEditor/Managed/GridEditor.cs:16){code}