On Tue, 16 Dec 2025 07:44:53 GMT, John Hendrikx <[email protected]> wrote:

>> When a Window is created with a certain X/Y coordinate to place it on a 
>> specific screen, and is subsequently shown for the first time, one of the 
>> first things it does is size the window according to the size of the Scene.  
>> It does this based on the render scale of the *primary* screen as it has not 
>> moved the peer yet to the correct screen.  After the scene has been sized, 
>> it is moved to the correct screen, triggering a change of render scale, but 
>> not a resizing of the Window (as this is only done once).
>> 
>> The result of this is that due to slight difference in render scale, the 
>> size calculated for the scene may be a few pixels off.  As the scene's 
>> preferred size is used for this calculation, even a few pixels too small can 
>> result in Labels being shown with ellipsis on the intended target screen 
>> with a different render scale.
>> 
>> When observing the render scale X or Y property, one can observe a change 
>> from 1.0 (the default value) to 2.0 (the primary screen's render scale) to 
>> another value (depending on the target screen).  However, the Window 
>> involved (being positioned by the user using setX()/setY() before it is 
>> shown) was never shown on the primary screen, yet the size calculation 
>> assumed it was.
>> 
>> To solve this problem, the peer should be moved to the correct screen 
>> **before** asking the Scene for its preferred size to use as the initial 
>> Window size.  Doing so (by adding an additional `applyBounds` call) also 
>> results in the render scale properties to only change once (or not at all) 
>> from their default value to the target screen's value (or not at all if the 
>> target screen is 1.0 scale).
>
> John Hendrikx has updated the pull request incrementally with one additional 
> commit since the last revision:
> 
>   Add more debug output

Note: I am using the latest standalone monkey tester 
https://github.com/andy-goryachev-oracle/MonkeyTest but a similar issue is 
present in the one that's currently in the main repo.

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PR Comment: https://git.openjdk.org/jfx/pull/2007#issuecomment-3661847218

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