Moved some variables from ItemBox to Item

src/timeline/component/item/Item.js

@@ -15,7 +15,9 @@ function Item (parent, data, options, defaultOptions) {
   this.defaultOptions = defaultOptions || {};
 
   this.selected = false;
-  this.visible = false;
+  this.displayed = false;
+  this.dirty = true;
+
   this.top = null;
   this.left = null;
   this.width = null;

src/timeline/component/item/ItemBox.js

@@ -20,9 +20,6 @@ function ItemBox (parent, data, options, defaultOptions) {
     }
   };
 
-  this.displayed = false;
-  this.dirty = true;
-
   // validate data
   if (data.start == undefined) {
     throw new Error('Property "start" missing in item ' + data);