In very rare, obscure UI scenarios, a "Handles.Repaint called outside an editor OnGUI" is sometimes logged.

Steps to reproduce:

1. Create a new Unity project using the Universal 2D template
2. Open the Tile Palette window (Window > 2D > Tile Palette)
3. Toggle the Tile Palette Brush Picks Overlay
4. Click the "Save" button in the Tile Palette Brush Picks Overlay
5. Toggle the Tile Palette Overlay
6. Create new Tile Palette
7. Observe the Console window

Actual results: "Handles.Repaint called outside an editor OnGUI" error is thrown

Expected results: No errors are thrown

Reproducible with versions: 6000.3.0a3, 6000.3.9f1, 6000.4.0b9, 6000.5.0a7

Not reproducible with versions: 6000.0.67f1, 6000.3.0a2

Tested on (OS): MacOS Silicon Tahoe 26.2

{}Note{}: The issue is inconsistent

{}UPDATE{}: This error is harmless.

It's intended to warn the user they're attempting to repaint a SceneView Handle outside of OnGUI(), which isn't allowed. However, in this scenario it's being triggered by a race-condition caused by a modal Dialog Box shown by an AuxWindow that's opened by a SceneView Overlay. In this case, the Repaint call is unnecessary and is simply ignored (but the error is still logged).

It doesn't occur on Windows because the platform timing of the modal UI is different than macOS resulting in different code paths being executed which sidesteps this scenario.