RFR: 8280482: Window transparency bug on Linux [v3]

[Alexander Zvegintsev]

On Fri, 21 Jul 2023 08:08:04 GMT, Tejesh R <tr at openjdk.org> wrote:

>> The bug mentions about transparency issue on Linux which actually got resolved with [JDK-8006421](https://bugs.openjdk.org/browse/JDK-8006421) fix. Now there is another problem related to the bug, which is screen selection going wrong during checking for new screen when the test is run. The problem is that (As seen in the pictures attached in bug) the transparency is lost for windows which are in screen 0 (default screen) too, which is not supposed to happen where windows on screen 1 should have lost there transparency. The main reason being the call to `toGlobal()` when window bounds are passed to `checkIfOnNewScreen` method. I didn't get the actual reason for `toGlobal` being used here (actually not required to check monitor number), but it actually doubled the X position of the window [here]( https://github.com/openjdk/jdk/blob/4b1403d06b99b91ddd89ad6e54669b0595f1f8e5/src/java.desktop/unix/classes/sun/awt/X11/XBaseWindow.java#L776). Removing `toGlobal` solve the issue and neith
 er didn't cause any regression (existing test + the reason `toGlobal()` was added [JDK-8143295](https://bugs.openjdk.org/browse/JDK-8143295)).
>> 
>> The automated test fails if GC is changed for windows within screen 0 (default screen). CI testing is green.
>
> Tejesh R has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Copywrite year update
>  - Review fix

test/jdk/java/awt/Multiscreen/MultiScreenCheckScreenIDTest.java line 113:

> 111:                     }
> 112:                 } else if (windowList.get(windowList.size() - 1).getBounds().
> 113:                         intersects(screens[1].getDefaultConfiguration().getBounds())) {

What if user has more than 2 screens?
It looks like the 3rd and subsequent screens are not tested.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14825#discussion_r1270480983