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

@@ -407,10 +407,16 @@
     @Override
     public void setModalBlocked(Dialog blocker, boolean blocked) {
         synchronized (getPeerTreeLock()) {
             this.blocker = blocked ? (LWWindowPeer)blocker.getPeer() : null;
         }
+        
+        if (blocked) {
+            platformWindow.modallyBlocked();
+        } else {
+            platformWindow.modallyUnblocked();
+        }
     }
 
     @Override
     public void updateMinimumSize() {
         Dimension d = null;