Reproduction steps:
1. Create a new project
2. GameObject > UI Toolkit > Panel Renderer
3. Select newly created GameObject and press “New” button in the Inspector to create UI Document
4. Double-click on the UI Document to open UI Builder window
5. Drag and drop any Element into UI Builder Hierarchy
6. Enter large value into any of the Spacing Padding section fields in the Inspector (e.g. “9000”)
7. Add a Filter in the Filter section (e.g. Tint)
8. Move the mouse cursor around the Editor and observe the Editor windows
Actual result: Gray artifacts flicker on Editor windows whenever the mouse cursor is moved
Expected result: No gray artifacts flicker on Editor windows
Reproducible with: 6000.3.0a1, 6000.3.20f1, 6000.5.5f1, 6000.6.0b5, 6000.7.0a3
Couldn’t reproduce with: 6000.0.80f1, 60000.2.0a10 (No Filter section)
Reproduced on: macOS Tahoe 26.5 (M4)
Not reproduced on: Windows 11, Ubuntu 24.04