RFR: 8280482: Window transparency bug on Linux [v2]

[Tejesh R]

On Thu, 20 Jul 2023 19:20:52 GMT, Alexander Zvegintsev <azvegint at openjdk.org> wrote:

>> _I suggest to check if window's GraphicsConfiguration is associated with correct screen device
>> (e.g. check if the window bounds within the window.getGraphicsConfiguration().getDevice().getBounds())._
>> I didn't get this suggestion. Does it means to compare GC or the position of every `window` with corresponding `window.getGraphicsConfiguration().getBounds()`.......? `window.getGraphicsConfiguration().getBounds()` shows same for all the windows, either in primary/secondary monitor.
>
>> shows same for all the windows, either in primary/secondary monitor.
> 
> For me it is not true:
> 
> [GCBounds.java.txt](https://github.com/openjdk/jdk/files/12113425/GCBounds.java.txt)
> 
>> Screen bounds java.awt.Rectangle[x=0,y=0,width=2560,height=1440]
> Frame gc bounds: java.awt.Rectangle[x=0,y=0,width=2560,height=1440]
> Screen bounds java.awt.Rectangle[x=2560,y=0,width=1920,height=1200]
> Frame gc bounds: java.awt.Rectangle[x=2560,y=0,width=1920,height=1200]

Looks like I was checking for `window.getGraphicsConfiguration().getBounds()` right after making it visible, waiting for the events to finish up gives right values. I have updated the test and validation is moved outside the GC change event. Tested multiple times and the test looks fine.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14825#discussion_r1270364023