ADDITIONAL SYSTEM INFORMATION :
Windows 10, Java 14.02

A DESCRIPTION OF THE PROBLEM :
This could be regression of an older bug, JDK-8119136. It is possible that this is a regression.

FX fails to create a popup window, randomly. Depending on the chain of events, this can leave the UI in an indeterminate state (unusable).

This was reported here, but I cannot see a bug report corresponding to it. Test case is derived from this post.

https://community.oracle.com/tech/developers/discussion/4346851/javafx-could-not-create-platform-window

This is a critical bug, as it renders our application useless after a time.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the test case.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
It will continue to run to max count
ACTUAL -
It crashes randomly before max count

---------- BEGIN SOURCE ----------
public class FXpopupBug extends Application {

@Override

public void start(Stage primaryStage) {
try {
System.out.println("javafx.runtime.version: " + System.getProperties().get("javafx.runtime.version"));

Stage stage = new Stage();

Scene scene = new Scene(new StackPane());

stage.setScene(scene);

stage.show();

Popup popOver = new Popup();

for (int i = 0; i < 99999; i++) {

popOver.show(scene.getRoot(), 1, 1);

popOver.hide();

System.out.println(i);

}
}catch(Throwable e) {
e.printStackTrace();
System.exit(0);
}
}

public static void main(String[] args) {

launch(args);

}

}
---------- END SOURCE ----------

FREQUENCY : often