Emojis in syntax highlighted code area cause other characters to not display

[mindolph]

When entering a specific pattern of emoji characters in a syntax-highlighted CodeArea, the characters following the emoji characters cannot be displayed.

Code to reproduce the problem:

String text = "* 😂 hello";
codeArea.replaceText(text);
StyleSpansBuilder<Collection<String>> spansBuilder = new StyleSpansBuilder<>();
spansBuilder.add(List.of("md-list"), 2);
spansBuilder.add(Collections.emptyList(), 9);
codeArea.setStyleSpans(0, spansBuilder.create());

In the above example, the hello after the 😂 is not displayed at all, even when selected with cursor.

But, what Interesting is, If the text is * 😂😂 hello with 2 emoji characters, the display works well.

[Jugen]

Mmm, so historically JavaFX has had problems with Emoji support especially it seems on MacOS.

In order to rule out if this is a RichTextFX issue or a JavaFX issue, could you please run the same test with TextArea.

If it works with TextArea but not with RichTextFX then please give feedback providing your simple test program (with both a TextArea and a CodeArea) and also specify your OS and Java version. Thanks.

[mindolph]

The JDK version is 25 and the JavaFX version is 25 either, the OS is macOS 15.7.1.
I have tried that the emoji does work well with TextArea:

String text = "* 😂 hello";
// TextArea
textArea.setText(text);
// CodeArea
codeArea.replaceText(text);
StyleSpansBuilder<Collection<String>> spansBuilder = new StyleSpansBuilder<>();
spansBuilder.add(List.of("md-list"), 2);
spansBuilder.add(Collections.emptyList(), 9);
codeArea.setStyleSpans(0, spansBuilder.create());

[Jugen]

I tried your code snippet on Windows 10 with JavaFX 25 and it displays fine.
So, this seems to be a problem on macOS - to which I unfortunately don't have access to.
Hopefully somebody else can have a look into this and figure it out.

[mindolph]

I tried your code snippet on Windows 10 with JavaFX 25 and it displays fine. So, this seems to be a problem on macOS - to which I unfortunately don't have access to. Hopefully somebody else can have a look into this and figure it out.

You are right, this issue is platform related and only happens on macOS. I tried it on Windows, the display does work well.