Displaying modified indicator with custom editor (JCEF)

Hi

I am struggling to get the modified indicator (the asterisk in the editor tab), with a custom editor (JCEF based).

I know about `FileEditor.PROP_MODIFIED`, I have implemented the property change listeners as indicated in this comment (and elsewhere)

https://intellij-support.jetbrains.com/hc/en-us/community/posts/206117739/comments/206692809

My editor looks like

class ExcalidrawEditor(
    private val project: Project,
    private val file: VirtualFile
) : FileEditor,
    EditorColorsListener,
    DumbAware {

  ...
  private val viewController = ... // the component handling JCEF and webapp
  private val propertyChangeSupport = PropertyChangeSupport(this)
  private var modified = false

  init {
    ...
    viewController.changedPayload.adviseNotNull(lifetime) { content ->
      modified = true
      ApplicationManager.getApplication().invokeLater {
        ApplicationManager.getApplication().runWriteAction {
            propertyChangeSupport.firePropertyChange(FileEditor.PROP_MODIFIED, false, true)
        }
      }
  }
  ...

  override fun isModified(): Boolean {
    return modified
  }

  override fun addPropertyChangeListener(listener: PropertyChangeListener) {
    propertyChangeSupport.addPropertyChangeListener(listener);
  }

  override fun removePropertyChangeListener(listener: PropertyChangeListener) {
    propertyChangeSupport.removePropertyChangeListener(listener);
  }
}

The add/remove property change listener are called, when the content is changed in the browser frame the `changedPayload` (an `IPropertyView` from JetBrains/rd project) is notified as expected, and the code execute just fines in the `runWriteAction` lambda.

However the asterisk is still not shown.

Thanks in advance for any guidance.