src/macosx/classes/sun/lwawt/macosx/LWCToolkit.java

*** 75,86 ****
--- 75,95 ----
              }
          });
          if (!GraphicsEnvironment.isHeadless()) {
              initIDs();
          }
+         inAWT = AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
+             @Override
+             public Boolean run() {
+                 return !Boolean.parseBoolean(System.getProperty("javafx.embed.singleThread", "false"));
+             }
+         });
      }
  
+     /* If we operate in FX/AWT single threaded mode the nested loop should run in default mode */
+     private static final boolean inAWT;
+ 
      public LWCToolkit() {
          SunToolkit.setDataTransfererClassName("sun.lwawt.macosx.CDataTransferer");
  
          areExtraMouseButtonsEnabled = Boolean.parseBoolean(System.getProperty("sun.awt.enableExtraMouseButtons", "true"));
          //set system property if not yet assigned
*** 699,709 ****
       *                      processing which could break Appkit.
       *                      (One known example is when the window is resized with the mouse)
       *
       *                      if false - all events come after exit form the nested loop
       */
!     static native void doAWTRunLoop(long mediator, boolean processEvents);
      static native void stopAWTRunLoop(long mediator);
  
      private native boolean nativeSyncQueue(long timeout);
  
      @Override
--- 708,721 ----
       *                      processing which could break Appkit.
       *                      (One known example is when the window is resized with the mouse)
       *
       *                      if false - all events come after exit form the nested loop
       */
!     static void doAWTRunLoop(long mediator, boolean processEvents) {
!         doAWTRunLoopImpl(mediator, processEvents, inAWT);
!     }
!     static private native void doAWTRunLoopImpl(long mediator, boolean processEvents, boolean inAWT);
      static native void stopAWTRunLoop(long mediator);
  
      private native boolean nativeSyncQueue(long timeout);
  
      @Override