The data-protocol is not supported if the WebView runs in sandbox mode.

Example HTML code:
<img src='data:image/jpeg;base64,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' />

If run in non-sandbox mode this is correctly displayed as an image (checkmark on green circle).
But in sandbox mode it shows as broken image (could not be loaded).

When i first load this HTML no exception is logged. But if i right click on the image and choose "open in new window" then the following exception is triggered twice:

java.security.AccessControlException: access denied ("java.net.NetPermission" "specifyStreamHandler")
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at sun.plugin2.applet.AWTAppletSecurityManager.checkPermission(Unknown Source)
at java.net.URL.checkSpecifyHandler(Unknown Source)
at java.net.URL.<init>(Unknown Source)
at com.sun.webkit.network.URLs.newURL(Unknown Source)
at com.sun.webkit.network.URLs.newURL(Unknown Source)
at com.sun.webkit.network.NetworkContext.canHandleURL(Unknown Source)
at com.sun.webkit.ContextMenu.twkHandleItemSelected(Native Method)
at com.sun.webkit.ContextMenu.access$000(Unknown Source)
at com.sun.webkit.ContextMenu$ShowContext.notifyItemSelected(Unknown Source)
at com.sun.javafx.webkit.theme.ContextMenuImpl.lambda$show$77(Unknown Source)
at com.sun.javafx.webkit.theme.ContextMenuImpl$$Lambda$173/21567976.handle(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source)
at javafx.event.Event.fireEvent(Unknown Source)
at javafx.scene.control.MenuItem.fire(Unknown Source)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.doSelect(Unknown Source)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.lambda$createChildren$324(Unknown Source)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer$$Lambda$189/27816829.handle(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source)
at javafx.event.Event.fireEvent(Unknown Source)
at javafx.scene.Scene$MouseHandler.process(Unknown Source)
at javafx.scene.Scene$MouseHandler.access$1500(Unknown Source)
at javafx.scene.Scene.impl_processMouseEvent(Unknown Source)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Unknown Source)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(Unknown Source)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(Unknown Source)
at com.sun.glass.ui.View.handleMouseEvent(Unknown Source)
at com.sun.glass.ui.View.notifyMouse(Unknown Source)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$141(Unknown Source)
at com.sun.glass.ui.win.WinApplication$$Lambda$53/7629379.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)


Maybe this also can be fixed with a doPrivileged() block?