src/java.desktop/macosx/native/libawt_lwawt/awt/AWTWindow.m

*** 883,904 ****
  
              NSPoint p = [NSEvent mouseLocation];
              NSRect frame = [self.nsWindow frame];
              NSRect contentRect = [self.nsWindow contentRectForFrameRect:frame];
  
-             // Check if the click happened in the non-client area (title bar)
-             if (p.y >= (frame.origin.y + contentRect.size.height)) {
                  JNIEnv *env = [ThreadUtilities getJNIEnvUncached];
                  jobject platformWindow = [self.javaPlatformWindow jObjectWithEnv:env];
                  if (platformWindow != NULL) {
                      // Currently, no need to deliver the whole NSEvent.
                      static JNF_MEMBER_CACHE(jm_deliverNCMouseDown, jc_CPlatformWindow, "deliverNCMouseDown", "()V");
                      JNFCallVoidMethod(env, platformWindow, jm_deliverNCMouseDown);
-                     (*env)->DeleteLocalRef(env, platformWindow);
                  }
              }
          }
  }
  
  - (void)constrainSize:(NSSize*)size {
      float minWidth = 0.f, minHeight = 0.f;
  
--- 883,912 ----
  
              NSPoint p = [NSEvent mouseLocation];
              NSRect frame = [self.nsWindow frame];
              NSRect contentRect = [self.nsWindow contentRectForFrameRect:frame];
              
              JNIEnv *env = [ThreadUtilities getJNIEnvUncached];
              jobject platformWindow = [self.javaPlatformWindow jObjectWithEnv:env];
+             
+             // Check if the click happened in the non-client area (title bar)
+             if (p.y >= (frame.origin.y + contentRect.size.height)) {
                  if (platformWindow != NULL) {
+                     // Toggle full screen upon double click on title bar.
+                     if([event clickCount] == 2) {
+                         static JNF_MEMBER_CACHE(jm_deliverNCDblClick, jc_CPlatformWindow, "deliverNCDblClick", "()V");
+                         JNFCallVoidMethod(env, platformWindow, jm_deliverNCDblClick);
+                     } else {
                          // Currently, no need to deliver the whole NSEvent.
                          static JNF_MEMBER_CACHE(jm_deliverNCMouseDown, jc_CPlatformWindow, "deliverNCMouseDown", "()V");
                          JNFCallVoidMethod(env, platformWindow, jm_deliverNCMouseDown);
                      }
                  }
              }
+             
+             (*env)->DeleteLocalRef(env, platformWindow);
+         }
  }
  
  - (void)constrainSize:(NSSize*)size {
      float minWidth = 0.f, minHeight = 0.f;