Window transparency bug on Linux

In a multi-screen setup, some windows could lose translucency.

The sample app creates a grid of translucent windows that covers the screen.

Expected results:

The entire screen is covered with windows which have the specified level of translucency.

Actual results:

Some of the areas of the screen appear darker than expected as if that window lost translucency.


Originally reported on client-dev mailing list:
https://mail.openjdk.java.net/pipermail/client-libs-dev/2022-January/002064.html