RFR: 8242419: JFXPanel: MouseEvent always reports that Primary button changed state if held

[Andy Goryachev]

On Wed, 5 Jul 2023 03:07:01 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

> If an EventHandler or EventFilter for a mouse button is attached to a scene within a JFXPanel and the **primary mouse button** is held, any mouse button click will create an event such that event.getButton().name() wrongly returns PRIMARY, even if the secondary or middle button was clicked. 
> This is because `SwingEvents.mouseButtonToEmbedMouseButton()` overwrites the button name after checking the modifier value. 
> For mouse click with primary button  `mouseButtonToEmbedMouseButton` is first called with `BUTTON1 `and modifier `BUTTON1_DOWN_MASK `(ie 1024) and then when secondary button(ie right button is clicked) `mouseButtonToEmbedMouseButton` is called with `BUTTON3 `and modifier `BUTTON3_DOWN_MASK | BUTTON1_DOWN_MASK` (ie 5120) 
> and when secondary button is released, `mouseButtonToEmbedMouseButton` is again called with `BUTTON3 `but with modifier `BUTTON1_DOWN_MASK `(1024) resulting in button being declared PRIMARY.
> 
> Fix is to make sure not to overwrite button name if a button name is already assigned.

modules/javafx.swing/src/main/java/com/sun/javafx/embed/swing/SwingEvents.java line 84:

> 82:         }
> 83:         // Fix for RT-15457: we should report mouse buttons for mouse drags
> 84:         if (abstractButton == AbstractEvents.MOUSEEVENT_NONE_BUTTON) {

minor: the placement of the old comment suggests that it applies to like 84 (this change).  Perhaps the comment should be moved down to the line 85.

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PR Review Comment: https://git.openjdk.org/jfx/pull/1170#discussion_r1253538089