ADDITIONAL SYSTEM INFORMATION :
macOS Monterey 12.4
openjdk version "17.0.3" 2022-04-19
OpenJDK Runtime Environment (build 17.0.3+7)
OpenJDK 64-Bit Server VM (build 17.0.3+7, mixed mode, sharing)

A DESCRIPTION OF THE PROBLEM :
Popup and its subclasses cannot input text from InputMethod.

While this problem is easily reproducible and has a significant impact on users of CJK language environments who input text using an IME, it is, however, a potential problem for developers of language environments that do not use an IME.
As a result, this creates a situation where developers who do not use IMEs unintentionally provide libraries and applications that do not allow text input.

The test programa include a work-around for this problem.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. start the test program
2. Press the Popup button (or PopupControl) to open the popup
3. Enter text via InputMethod

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The IME candidate window will appear below the text input control. By committing the input, the text is inserted into the text control.

ACTUAL -
The IME candidate window is displayed at the origin of the screen.
Committing the input does not insert text into the text control.

---------- BEGIN SOURCE ----------

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.CheckBox;
import javafx.scene.control.Label;
import javafx.scene.control.PopupControl;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;
import javafx.scene.control.ToolBar;
import javafx.scene.input.InputMethodEvent;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyEvent;
import javafx.scene.layout.Background;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.stage.Popup;
import javafx.stage.Stage;
import javafx.stage.StageStyle;

public class PopupTest extends Application {
public void start(Stage stage) {
stage.setTitle("Popup Test");

Button popupButton = new Button("Popup");
Button popupControlButton = new Button("PopupControl");
Button stageButton = new Button("Stage (Workaround)");
CheckBox focusTraversable = new CheckBox("focusTraversable");

focusTraversable.setSelected(true);

popupButton.focusTraversableProperty().bind(focusTraversable.selectedProperty());
popupControlButton.focusTraversableProperty().bind(focusTraversable.selectedProperty());
stageButton.focusTraversableProperty().bind(focusTraversable.selectedProperty());

Popup popup = createPopup();
PopupControl popupControl = createPopupControl();
Stage stage2 = createStage();
stage2.initOwner(stage);

popupButton.setOnAction(e->popup.show(stage));
popupControlButton.setOnAction(e->popupControl.show(stage));
stageButton.setOnAction(e->stage2.show());

ToolBar toolBar = new ToolBar(popupButton, popupControlButton, stageButton, focusTraversable);
BorderPane root = new BorderPane(createContent());
root.setTop(toolBar);
Scene scene = new Scene(root, 450, 360);
stage.setScene(scene);

stage.show();
}

private Popup createPopup() {
Popup popup = new Popup();
popup.setAutoHide(true);
VBox content = createContent();
popup.getContent().add(content);
return popup;
}

private PopupControl createPopupControl() {
PopupControl popup = new PopupControl();
popup.setAutoHide(true);
VBox content = createContent();
popup.getScene().setRoot(content);
return popup;
}

private Stage createStage() {
Stage stage = new Stage(StageStyle.TRANSPARENT);
stage.focusedProperty().addListener((ob,oldValue,newValue)->{
if(!newValue.booleanValue()) {
stage.hide();
}
});
stage.addEventFilter(KeyEvent.KEY_PRESSED, (e)->{
if(e.getCode() == KeyCode.ESCAPE) {
stage.hide();
}
});
VBox content = createContent();
BorderPane root = new BorderPane(content);
root.setBackground(Background.EMPTY);
root.setPadding(new Insets(6, 10, 10, 10));
Scene scene = new Scene(root, Color.TRANSPARENT);
stage.setScene(scene);

// To stabilize the state of the IME
// we need to takeaway the focus of the text input control.
stage.setOnHidden(e->root.requestFocus());
stage.setOnShown((e)->content.lookup(".text-field").requestFocus());

return stage;
}

private VBox createContent() {
TextField textField = new TextField();
TextArea textArea = new TextArea();

textField.addEventFilter(InputMethodEvent.ANY, e->{
System.out.println(e);
});
textArea.addEventFilter(InputMethodEvent.ANY, e->{
System.out.println(e);
});

VBox content = new VBox(16, new Label("Enter text using InputMethod"), textField, textArea);
content.setPrefSize(300, 200);
content.setPadding(new Insets(10));
content.setStyle("-fx-background-color:#fefefe; -fx-effect:dropshadow(gaussian,rgba(0,0,0,0.2),12,0,0,4)");
return content;
}

public static void main(String[] args) {
launch(args);
}
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
See attached test source code.

FREQUENCY : always