#4 do not leak tick listeners!

app/src/app.js

@@ -152,6 +152,7 @@ export default class App {
             if (progress >= 1) {
                 PIXI.ticker.shared.remove(tick)
                 that.stage.removeChild(pod)
+                pod.destroy()
                 originalPod.visible = true
             }
         }
@@ -167,7 +168,7 @@ export default class App {
         pod.position = globalPosition.clone()
         pod.alpha = 1
         pod._progress = 1
-        originalPod.visible = false
+        originalPod.destroy()
         const that = this
         const tick = function(t) {
             // progress goes from 1 to 0
@@ -181,6 +182,7 @@ export default class App {
             if (progress <= 0) {
                 PIXI.ticker.shared.remove(tick)
                 that.stage.removeChild(pod)
+                pod.destroy()
             }
         }
         PIXI.ticker.shared.add(tick)
@@ -214,6 +216,8 @@ export default class App {
                     window.setTimeout(function() {
                         that.animatePodDeletion(pod, globalPos)
                     }, 100 * changes)
+                } else {
+                    pod.destroy()
                 }
                 changes++
             }

app/src/pod.js

@@ -19,6 +19,13 @@ export class Pod extends PIXI.Graphics {
         }
     }
 
+    destroy() {
+        if (this.tick) {
+            PIXI.ticker.shared.remove(this.tick, this)
+        }
+        super.destroy()
+    }
+
     animateMove(time) {
         const deltaX = this._targetPosition.x - this.position.x
         const deltaY = this._targetPosition.y - this.position.y
@@ -108,7 +115,6 @@ export class Pod extends PIXI.Graphics {
 
     draw() {
 
-
         // pod.status.containerStatuses might be undefined!
         const containerStatuses = this.pod.status.containerStatuses || []
         var ready = 0
@@ -225,10 +231,12 @@ export class Pod extends PIXI.Graphics {
             }
         }
 
-        if (newTick) {
+        if (newTick && newTick != this.tick) {
             this.tick = newTick
+            // important: only register new listener if it does not exist yet!
+            // (otherwise we leak listeners)
             PIXI.ticker.shared.add(this.tick, this)
-        } else if (this.tick) {
+        } else if (!newTick && this.tick) {
             PIXI.ticker.shared.remove(this.tick, this)
             this.tick = null
             this.alpha = this._progress