Reproduction steps:
1. Create a new Universal 2D project
2. Create any Sprite (Create > 2D > Sprite)
3. Select newly created Sprite and press “Open Sprite Editor” button in the Inspector
4. Observe “Toggle Sprite Editor locks” button in Sprite Editor

Actual result: Button icon is blurry and difficult to see
Expected result: Button icon is sharp

Reproducible with: 6000.3.0a1, 6000.3.15f1, 6000.4.7f1, 6000.5.0b8, 6000.6.0a5
Not reproducible with: 6000.2.0b2
Couldn't reproduce with: 6000.0.75f1 (No “Toggle Sprite Editor locks” button)

Reproduced on: Ubuntu 24.04
Not reproduced with: macOS Tahoe 26.4 (M4), Windows 11