FULL PRODUCT VERSION :
java version "1.8.0_111"
Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.111-b14, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 10.0.10586]

A DESCRIPTION OF THE PROBLEM :
If a WebView is scrolled far enough and then enlarged, the dirty region is not properly set, causing only a part of the WebView to update on subsequent scrolling.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Start the sample application, preferably with -Dprism.showdirty=true
2. Wait until the website is loaded
3. Scroll all the way down
4. Enlarge the window
5. Scroll up again

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The WebView should render normally
ACTUAL -
Only the initially visible part is updating 100% of the time, the rest of the page updates sometimes.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

public class WebViewBug extends Application {

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

  @Override
  public void start(Stage primaryStage) throws Exception {
    WebView webView = new WebView();
    WebEngine engine = webView.getEngine();
    engine.load("http://www.oracle.com");
    primaryStage.setScene(new Scene(webView, 200, 200));
    primaryStage.show();
  }
}

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

CUSTOMER SUBMITTED WORKAROUND :
-Dprism.dirtyopts=false