java.lang.AssertionError: *** pgAccessCount underflow
   at javafx.scene.Scene.impl_setAllowPGAccess(Scene.java:467)
   at javafx.scene.web.WebView.handleStagePulse(WebView.java:1003)
   at javafx.scene.web.WebView.lambda$new$29(WebView.java:280)
   at com.sun.javafx.tk.Toolkit.lambda$runPulse$30(Toolkit.java:355)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:354)
   at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:378)
   at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:510)
   at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:490)
   at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$404(QuantumToolkit.java:319)
   at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
   at com.sun.glass.ui.gtk.GtkApplication._runLoop(GtkApplication.java:0)
   at com.sun.glass.ui.gtk.GtkApplication.lambda$null$49(GtkApplication.java:139)
   at java.lang.Thread.run(Thread.java:745)