When dragging out the content of a WebView (eg. google maps) there occur different errors. Dragging meens: Click on the webpage content, hold the primary mouse key drag it out of the Stage (eg. to the desktop) and release the mouse key.
When zooming, panning and then dragging content out many times I got these errors amongst others:

Outstanding resource locks detected:
D3D Vram Pool: 88.682.168 used (16,5%), 102.427.732 target (19,1%), 536.870.912 max
245 total resources being managed
average resource age is 19,3 frames
0 resources at maximum supported age (0,0%)
26 resources marked permanent (10,6%)
19 resources have had mismatched locks (7,8%)
19 resources locked (7,8%)
123 resources contain interesting data (50,2%)
0 resources disappeared (0,0%)

java.lang.IllegalArgumentException: Image dimensions must be > 0
at com.sun.prism.Image.<init>(Image.java:292)
at com.sun.prism.Image.<init>(Image.java:268)
at com.sun.prism.Image.fromByteBgraPreData(Image.java:111)
at com.sun.javafx.webkit.prism.RTImage.getImage(RTImage.java:61)
at com.sun.javafx.webkit.prism.PrismImage.getPlatformImage(PrismImage.java:57)
at com.sun.javafx.webkit.UIClientImpl.startDrag(UIClientImpl.java:277)
at com.sun.webkit.WebPage.fwkStartDrag(WebPage.java:2160)
at com.sun.webkit.WebPage.twkProcessMouseEvent(Native Method)
at com.sun.webkit.WebPage.dispatchMouseEvent(WebPage.java:759)
at javafx.scene.web.WebView.processMouseEvent(WebView.java:1021)
at javafx.scene.web.WebView.lambda$registerEventHandlers$32(WebView.java:1144)
at javafx.scene.web.WebView$$Lambda$82/1815779990.handle(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3758)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3486)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2495)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:350)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:275)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$350(GlassViewEventHandler.java:385)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$$Lambda$141/1586881300.get(Unknown Source)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:404)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:384)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:927)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$145(WinApplication.java:101)
at com.sun.glass.ui.win.WinApplication$$Lambda$36/2117255219.run(Unknown Source)
at java.lang.Thread.run(Thread.java:745)


Here is an example code which I used to produce these errors:

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

public class GoogleMapsDragException extends Application {

@Override
public void start(Stage primaryStage) throws Exception {
System.setProperty("java.net.useSystemProxies", "true");
WebView webView = new WebView();
WebEngine webEngine = webView.getEngine();
webEngine.load("http://maps.google.com");
primaryStage.setScene(new Scene(webView));
primaryStage.show();
}

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

}