An extended stage seems to hang after a drag and drop operation. Note that in
the attached reproducer, the application seems unresponsive until the mouse
cursor leaves and re-enters the application window:
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.input.ClipboardContent;
import javafx.scene.input.Dragboard;
import javafx.scene.input.TransferMode;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.HeaderBar;
import javafx.stage.Stage;
import javafx.stage.StageStyle;
public class DragDropTest extends Application {
@Override
public void start(Stage primaryStage) {
primaryStage.initStyle(StageStyle.EXTENDED);
// Create drag source
Label dragSource = new Label("Drag me!");
dragSource.setStyle("-fx-background-color: lightblue; -fx-padding:
10px");
// Create drop target
Label dropTarget = new Label("Drop here!");
dropTarget.setStyle("-fx-background-color: lightcoral; -fx-padding:
20px; -fx-min-width: 150px; -fx-min-height: 100px;");
// Set up drag detection
dragSource.setOnDragDetected(event -> {
Dragboard dragboard =
dragSource.startDragAndDrop(TransferMode.COPY);
ClipboardContent content = new ClipboardContent();
content.putString("Hello from drag source!");
dragboard.setContent(content);
event.consume();
});
// Set up drag over
dropTarget.setOnDragOver(event -> {
if (event.getGestureSource() != dropTarget &&
event.getDragboard().hasString()) {
event.acceptTransferModes(TransferMode.COPY);
}
event.consume();
});
// Set up drag entered (visual feedback)
dropTarget.setOnDragEntered(event -> {
if (event.getGestureSource() != dropTarget &&
event.getDragboard().hasString()) {
dropTarget.setStyle("-fx-background-color: lightgreen;
-fx-padding: 20px; -fx-min-width: 150px; -fx-min-height: 100px;");
}
event.consume();
});
// Set up drag exited (reset visual feedback)
dropTarget.setOnDragExited(event -> {
dropTarget.setStyle("-fx-background-color: lightcoral; -fx-padding:
20px; -fx-min-width: 150px; -fx-min-height: 100px;");
event.consume();
});
// Set up drop
dropTarget.setOnDragDropped(event -> {
Dragboard dragboard = event.getDragboard();
boolean success = false;
if (dragboard.hasString()) {
dropTarget.setText("Dropped: " + dragboard.getString());
success = true;
}
event.setDropCompleted(success);
event.consume();
});
// Layout
HBox layout = new HBox(20);
layout.getChildren().addAll(dragSource, dropTarget);
layout.setStyle("-fx-padding: 20px;");
var root = new BorderPane();
root.setTop(new HeaderBar());
root.setCenter(layout);
Scene scene = new Scene(root, 400, 200);
// Test with different stage styles
// Change this line to test different styles:
// primaryStage.initStyle(StageStyle.DECORATED); // Try: UNDECORATED,
UTILITY, TRANSPARENT, etc.
primaryStage.setTitle("Drag and Drop Test");
primaryStage.setScene(scene);
primaryStage.show();
}
}
The cause for this bug is that a drag-and-drop operation can cause a spurious
`WM_MOUSELEAVE` message to be sent to the window, even though the mouse cursor
is still within the client area. This messes up the mouse tracking state in
GlassWindow.
-------------
Commit messages:
- fix spurious WM_MOUSELAVE on DnD
Changes: https://git.openjdk.org/jfx/pull/2003/files
Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=2003&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8367557
Stats: 59 lines in 1 file changed: 33 ins; 24 del; 2 mod
Patch: https://git.openjdk.org/jfx/pull/2003.diff
Fetch: git fetch https://git.openjdk.org/jfx.git pull/2003/head:pull/2003
PR: https://git.openjdk.org/jfx/pull/2003
