--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -5448,16 +5448,27 @@ PanGestureTypeForEvent(NSEvent* aEvent)
 
 - (NSRect)firstRectForCharacterRange:(NSRange)aRange
                          actualRange:(NSRangePointer)actualRange
 {
   NS_ENSURE_TRUE(mTextInputHandler, NSMakeRect(0.0, 0.0, 0.0, 0.0));
   return mTextInputHandler->FirstRectForCharacterRange(aRange, actualRange);
 }
 
+- (void)quickLookWithEvent:(NSEvent*)event
+{
+  // Show dictionary by current point
+  WidgetContentCommandEvent
+    contentCommandEvent(true, eContentCommandLookUpDictionary, mGeckoChild);
+  NSPoint point = [self convertPoint:[event locationInWindow] fromView:nil];
+  contentCommandEvent.mRefPoint = mGeckoChild->CocoaPointsToDevPixels(point);
+  mGeckoChild->DispatchWindowEvent(contentCommandEvent);
+  // The widget might have been destroyed.
+}
+
 - (NSInteger)windowLevel
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK_RETURN;
 
   NS_ENSURE_TRUE(mTextInputHandler, [[self window] level]);
   return mTextInputHandler->GetWindowLevel();
 
   NS_OBJC_END_TRY_ABORT_BLOCK_RETURN(NSNormalWindowLevel);