Package Manager's Export package window is rendered with artifacts when Editor is running on OpenGL

Steps to reproduce:

1. Open the attached project
2. Open the Package Manager window
3. Open All Packages in Project tab
4. Select the test package
5. Press the Export button

Actual results: The Export Package window is rendered with artifacts. If the window is moved, other Editor windows become rendered in solid black and are no longer interactable

Expected results: The Export Package window is rendered correctly, can be interacted with and does not affect other Editor windows

Reproducible with versions: 6000.3.0a5, 6000.3.3f1, 6000.4.0b3, 6000.5.0a4

Can’t test with versions: 6000.0.65f1, 6000.3.0a4 (Export Package button was not yet available)

Reproudible on (OS): Ubuntu 24.04

Not reproducible on (OS): macOS 26.1

Notes:

• The issue does not reproduce on Ubuntu 24 when running the Editor with Vulkan