Input.addMoveCallback used to return the index of the callback entry in the internal moveCallbacks array. However as callbacks were removed the indexes became invalid, potentially causing a future Input.deleteMoveCallback to remove the wrong callback entirely or error. Input.deleteMoveCallback now takes the original callback and context as its parameters to ensure deletion safety.

Author: photonstorm

src/input/Input.js

@@ -441,30 +441,37 @@ Phaser.Input.prototype = {
     * 
     * It will be called every time the activePointer moves, which in a multi-touch game can be a lot of times, so this is best
     * to only use if you've limited input to a single pointer (i.e. mouse or touch).
+    * 
     * The callback is added to the Phaser.Input.moveCallbacks array and should be removed with Phaser.Input.deleteMoveCallback.
     * 
     * @method Phaser.Input#addMoveCallback
     * @param {function} callback - The callback that will be called each time the activePointer receives a DOM move event.
     * @param {object} context - The context in which the callback will be called.
-    * @return {number} The index of the callback entry. Use this index when calling Input.deleteMoveCallback.
     */
     addMoveCallback: function (callback, context) {
 
-        return this.moveCallbacks.push({ callback: callback, context: context }) - 1;
+        this.moveCallbacks.push({ callback: callback, context: context });
 
     },
 
     /**
-    * Removes the callback at the defined index from the Phaser.Input.moveCallbacks array
+    * Removes the callback from the Phaser.Input.moveCallbacks array.
     * 
     * @method Phaser.Input#deleteMoveCallback
-    * @param {number} index - The index of the callback to remove.
+    * @param {function} callback - The callback to be removed.
+    * @param {object} context - The context in which the callback exists.
     */
-    deleteMoveCallback: function (index) {
+    deleteMoveCallback: function (callback, context) {
+
+        var i = this.moveCallbacks.length;
 
-        if (this.moveCallbacks[index])
+        while (i--)
         {
-            this.moveCallbacks.splice(index, 1);
+            if (this.moveCallbacks[i].callback === callback && this.moveCallbacks[i].context === context)
+            {
+                this.moveCallbacks.splice(i, 1);
+                return;
+            }
         }
 
     },