ADDITIONAL SYSTEM INFORMATION :
$ uname -a
Linux neptune 4.19.0-16-amd64 #1 SMP Debian 4.19.181-1 (2021-03-19) x86_64 GNU/Linux
$ java -version
openjdk version "16.0.1" 2021-04-20
OpenJDK Runtime Environment AdoptOpenJDK-16.0.1+9 (build 16.0.1+9)
OpenJDK 64-Bit Server VM AdoptOpenJDK-16.0.1+9 (build 16.0.1+9, mixed mode, sharing)
$ ls /opt/javafx-sdk-16
legal lib


A DESCRIPTION OF THE PROBLEM :
In Linux, any JavaFX Node generates mouse moved events only for the following:

* The first mouse entry
* Any mouse exit
* Any mouse press

Mouse drag events are generated only for the mouse button release at the end of the drag.



STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Set the onMouseMoved or onMouseDragged on any JavaFX Node in Linux, or add an event filter or event handler for mouse moved or mouse dragged events. Add that node to a Stage, run the program, and move or drag the mouse over the node.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Every mouse movement should trigger a mouse moved or mouse dragged handler.
ACTUAL -
A Node generates mouse moved events only for the following:

* The first mouse entry
* Any mouse exit
* Any mouse press

Mouse drag events are generated only for the mouse button release at the end of the drag.


---------- BEGIN SOURCE ----------
import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.scene.canvas.Canvas;

public class MouseMoveTest
extends Application {
    @Override
    public void start(Stage stage) {
        Node node = new Canvas(600, 600);
        node.setOnMouseClicked(e ->
            System.out.printf("Click: %.1f, %.1f%n",
                e.getScreenX(), e.getScreenY()));
        node.setOnMouseDragged(e ->
            System.out.printf("Drag: %.1f, %.1f%n",
                e.getScreenX(), e.getScreenY()));
        node.setOnMouseMoved(e ->
            System.out.printf("Move: %.1f, %.1f%n",
                e.getScreenX(), e.getScreenY()));

        BorderPane pane = new BorderPane(node);

        stage.setScene(new Scene(pane));
        stage.setTitle("Mouse Move Test");
        stage.show();
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
This problem does not occur in Java 8, so using Java 8 could be one workaround. The problem exists in Java FX 11. I was not able to find a place from which to download JavaFX 9 or 10, so I don't know if the problem exists in those versions.

FREQUENCY : always