FIX: fix bugs with keyboard events

app/assets/javascripts/select-kit/components/multi-select.js.es6

@@ -117,7 +117,7 @@ export default SelectKitComponent.extend({
   },
 
   didPressBackspace(event) {
-    this.expand();
+    this.expand(event);
     this.keyDown(event);
     this._destroyEvent(event);
   },

app/assets/javascripts/select-kit/mixins/events.js.es6

@@ -28,6 +28,7 @@ export default Ember.Mixin.create({
     this.$filterInput()
       .off("change.select-kit")
       .off("keydown.select-kit")
+      .off("keypress.select-kit")
       .off("focus.select-kit")
       .off("focusin.select-kit");
   },
@@ -103,6 +104,9 @@ export default Ember.Mixin.create({
         this.set("isFocused", true);
         this._destroyEvent(event);
       })
+      .on("keypress.select-kit", (event) => {
+        event.stopPropagation();
+      })
       .on("keydown.select-kit", (event) => {
         const keyCode = event.keyCode || event.which;