Following the fix for JDK-8137050 we now get an AccessControlException when running any FX program that does not extend javafx.application.Application (e.g., a JFXPanel app or an application with a custom launcher) with a security manager. For example:

$ java -Djava.security.manager HelloJFXPanel
Exception in thread "AWT-EventQueue-0" java.security.AccessControlException: access denied ("java.util.PropertyPermission" "glass.gtk.uiScale" "read")
at java.security.AccessControlContext.checkPermission(AccessControlContext.java:468)
at java.security.AccessController.checkPermission(AccessController.java:894)
at java.lang.SecurityManager.checkPermission(SecurityManager.java:541)
at java.lang.SecurityManager.checkPropertyAccess(SecurityManager.java:1285)
at java.lang.System.getProperty(System.java:721)
at com.sun.glass.ui.gtk.GtkApplication.getFloat(GtkApplication.java:67)
at com.sun.glass.ui.gtk.GtkApplication.<init>(GtkApplication.java:114)
at com.sun.glass.ui.gtk.GtkPlatformFactory.createApplication(GtkPlatformFactory.java:41)
at com.sun.glass.ui.Application.run(Application.java:146)
at com.sun.javafx.tk.quantum.QuantumToolkit.startup(QuantumToolkit.java:257)
at com.sun.javafx.application.PlatformImpl.startup(PlatformImpl.java:231)
at com.sun.javafx.application.PlatformImpl.startup(PlatformImpl.java:141)
at javafx.embed.swing.JFXPanel.initFx(JFXPanel.java:211)
at javafx.embed.swing.JFXPanel.<init>(JFXPanel.java:226)
at helloworld.HelloJFXPanel.<init>(HelloJFXPanel.java:53)
at helloworld.HelloJFXPanel$3.run(HelloJFXPanel.java:102)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:313)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:759)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:712)
at java.awt.EventQueue$3.run(EventQueue.java:706)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:77)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:729)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:192)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:117)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:106)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:102)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:94)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:83)