Reproduction steps:
1. Open the attached “UnityBugReport.zip” project
2, Open the “SampleScene” Scene
3. Open the “DebugDrawLineDepthTest.cs” script from the Project Window
4. Comment out or delete the “SceneView.RepaintAll();” line and Save the script
5. Select the “DebugDrawLineDepthTest” GameObject from the Hierarchy
6. Move the mouse cursor from the Scene view to the Hierarchy Window
7. Observe the red line during 6th step in the Scene view

Expected result: The line does not flicker
Actual result: The line flickers

Reproducible with: 2021.3.45f1, 2022.3.51f1, 6000.0.25f1, 6000.1.0a2

Reproducible on: Windows 11
Not reproducible on: no other environment tested

Note:
- In the “DebugDrawLineDepthTest.cs” script uncommenting the{{SceneView.RepaintAll();}} line, stops the flickering, but makes the depthTest parameter not work at all