From d531ec231644d2d6febc5b4e85065dc1c1c2656d Mon Sep 17 00:00:00 2001
From: "Manu Mtz.-Almeida" <manu.valladolid@gmail.com>
Date: Fri, 4 Nov 2016 18:57:15 +0100
Subject: [PATCH] perf(menu): avoid change detection when it isn't needed
 (#8986)

---
 src/components/menu/menu-gestures.ts | 2 +-
 src/components/menu/menu.ts          | 6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/components/menu/menu-gestures.ts b/src/components/menu/menu-gestures.ts
index 257487770eb..21d6e02c2d3 100644
--- a/src/components/menu/menu-gestures.ts
+++ b/src/components/menu/menu-gestures.ts
@@ -21,6 +21,7 @@ export class MenuContentGesture extends SlideEdgeGesture {
       threshold: 0,
       maxEdgeStart: menu.maxEdgeStart || 50,
       maxAngle: 40,
+      zone: false,
       debouncer: new NativeRafDebouncer(),
       gesture: gestureCtrl.create('menu-swipe', {
         priority: GesturePriority.MenuSwipe,
@@ -58,7 +59,6 @@ export class MenuContentGesture extends SlideEdgeGesture {
       'z', z,
       'stepValue', stepValue);
 
-    ev.preventDefault();
     this.menu.swipeProgress(stepValue);
   }
 
diff --git a/src/components/menu/menu.ts b/src/components/menu/menu.ts
index 614483969cd..215956dbcf1 100644
--- a/src/components/menu/menu.ts
+++ b/src/components/menu/menu.ts
@@ -450,7 +450,11 @@ export class Menu {
       return;
     }
     this._getType().setProgessStep(stepValue);
-    this.ionDrag.emit(stepValue);
+
+    let ionDrag = this.ionDrag;
+    if (ionDrag.observers.length > 0) {
+      this._zone.run(ionDrag.emit.bind(ionDrag, stepValue));
+    }
   }
 
   /**