RFR: 8322784: JFXPanel calls InputMethodRequests on wrong thread

[Prasanta Sadhukhan]

On Thu, 18 Jan 2024 07:28:57 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

>> On Windows we need to ensure InputMethodRequests coming from JFXPanel are processed on the JavaFX application thread instead of the AWT EventQueue thread. This PR adds the runAndWait() calls to do that.
>> 
>> This would be difficult to test on Windows without a fix for [JDK-8090267](https://bugs.openjdk.org/browse/JDK-8090267) so I've included the fix first proposed by @prsadhuk in PR #1169. If a developer uses the sample code provided in the JavaDoc to create and show a JFXPanel there's a good chance the JFXPanel will get focus before the scene has been set. To ensure AWT always treats the JFXPanel as an active IME client we return a stub version of the InputMethodRequests object if there's no scene. AWT will continue to ask for the InputMethodRequests and once the scene has been set the panel will return a non-stub version.
>
> modules/javafx.swing/src/main/java/javafx/embed/swing/InputMethodSupport.java line 106:
> 
>> 104:                 });
>> 105:             }
>> 106:             if (stringValue == null) stringValue = "";
> 
> Not sure of FX coding guidelines but in JDK, even for a single statement, we need to put in braces

I guess this should add [JDK-8090267](https://bugs.openjdk.org/browse/JDK-8090267) through "/issue add" command

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PR Review Comment: https://git.openjdk.org/jfx/pull/1337#discussion_r1457033444