Some right-click context menus flicker a lot when Window Capture is running

[rhs31]

To reproduce this issue:

1. Open the DesktopLayouter example scene or any scene that is capturing all the windows, and hit play.
2. Open another instance of Unity, with any project, so that the second instance of the editor will be captured (it won't work by just using the same instance of Unity, because it will stop capturing when you try to do the next step).
3. In the second instance, right-click on an object in the hierarchy.

What you will probably see is that both the actual context menu, and the in-scene child window menu in the first instance of Unity, flicker a lot. This seems to happen both in-editor, and also in a build.

[rhs31]

It seems that switching the child window prefab to use Bit Blt stops the flickering. When not using Bit Blt, the amount of flickering is dependent on the frames per second that the window capture is updating with (I assume it flickers on every capture update frame).

Is there a way to make it so that the capture service detects when the window will flicker, and then use Bit Blt if it will?