From c9a166857122a080231a22e74d1ba84365cc1bbb Mon Sep 17 00:00:00 2001
From: Max Franz <maxkfranz@gmail.com>
Date: Thu, 8 Mar 2018 13:27:22 -0500
Subject: [PATCH] Backport 2.x : The `remove` event is emitted on already
 removed elements #2074 #2075

---
 src/collection/index.js               |  2 +-
 test/collection-graph-manipulation.js | 25 +++++++++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/collection/index.js b/src/collection/index.js
index e0c33b1b54..95d7b7685f 100644
--- a/src/collection/index.js
+++ b/src/collection/index.js
@@ -521,7 +521,7 @@ elesfn.remove = function( notifyRenderer ){
 
   function add( ele ){
     var alreadyAdded =  elesToRemoveIds[ ele.id() ];
-    if( alreadyAdded ){
+    if( ele.removed() || alreadyAdded ){
       return;
     } else {
       elesToRemoveIds[ ele.id() ] = true;
diff --git a/test/collection-graph-manipulation.js b/test/collection-graph-manipulation.js
index 9c3e31cb7b..e38acb327b 100644
--- a/test/collection-graph-manipulation.js
+++ b/test/collection-graph-manipulation.js
@@ -51,6 +51,31 @@ describe('Collection graph manipulation', function(){
       expect( cy.$('#n1n2') ).to.have.length(0);
     });
 
+    it('should not emit the remove event on an already removed element', function(){
+      var n1 = cy.$('#n1');
+      var emitted = false;
+
+      n1.remove();
+
+      n1.on('remove', function(){ emitted = true; });
+
+      n1.remove();
+
+      expect(emitted).to.be.false;
+    });
+
+    it('should only emit the remove event once', function(){
+      var n1 = cy.$('#n1');
+      var emits = 0;
+
+      n1.on('remove', function(){ emits++; });
+
+      n1.remove();
+      n1.remove();
+
+      expect(emits).to.equal(1);
+    });
+
   });
 
   describe('ele.removed()', function(){