diff --git a/ui/message_center/cocoa/tray_controller.h b/ui/message_center/cocoa/tray_controller.h
index 50e94fa850a960..62b03fbed27e03 100644
--- a/ui/message_center/cocoa/tray_controller.h
+++ b/ui/message_center/cocoa/tray_controller.h
@@ -26,10 +26,6 @@ MESSAGE_CENTER_EXPORT
 
   // View controller that provides this window's content.
   scoped_nsobject<MCTrayViewController> viewController_;
-
-  // An event monitor that listens for clicks outside the tray window to cause
-  // it to close.
-  id clickEventMonitor_;
 }
 
 // Designated initializer.
diff --git a/ui/message_center/cocoa/tray_controller.mm b/ui/message_center/cocoa/tray_controller.mm
index 437f8457a778cf..8ece243796dd13 100644
--- a/ui/message_center/cocoa/tray_controller.mm
+++ b/ui/message_center/cocoa/tray_controller.mm
@@ -48,26 +48,10 @@ - (id)initWithMessageCenterTray:(message_center::MessageCenterTray*)tray {
     NSView* contentView = [viewController_ view];
     [window setFrame:[contentView frame] display:NO];
     [window setContentView:contentView];
-
-    // The global event monitor will close the tray in response to events
-    // delivered to other applications, and -windowDidResignKey: will catch
-    // events within the application.
-    clickEventMonitor_ =
-        [NSEvent addGlobalMonitorForEventsMatchingMask:NSLeftMouseDownMask |
-                                                       NSRightMouseDownMask |
-                                                       NSOtherMouseDownMask
-            handler:^(NSEvent* event) {
-                [self windowDidResignKey:nil];
-            }];
   }
   return self;
 }
 
-- (void)dealloc {
-  [NSEvent removeMonitor:clickEventMonitor_];
-  [super dealloc];
-}
-
 - (void)close {
   [viewController_ onWindowClosing];
   [super close];