Simplified the background item support for empty/undefined contents

lib/timeline/component/css/item.css

@@ -54,8 +54,8 @@
   border: none;
   background-color: rgba(213, 221, 246, 0.4);
   box-sizing: border-box;
-  padding:0px;
-  margin:0px;
+  padding: 0;
+  margin: 0;
   top: 0;
   bottom: 0;
 }
@@ -74,13 +74,6 @@
   max-width: 100%;
   margin: 5px;
 }
-.vis.timeline .item.background .noContent {
-    position: absolute;
-    display: inline-block;
-    overflow: hidden;
-    max-width: 100%;
-    margin: 0px;
-}
 
 .vis.timeline .item.line {
   padding: 0;

lib/timeline/component/item/BackgroundItem.js

@@ -65,14 +65,7 @@ BackgroundItem.prototype.redraw = function() {
 
     // contents box
     dom.content = document.createElement('div');
-    if (this.data.content === undefined) {
-      dom.content.className = 'noContent';
-      this.emptyContent = true;
-    }
-    else {
-      dom.content.className = 'content';
-      this.emptyContent = false;
-    }
+    dom.content.className = 'content';
     dom.box.appendChild(dom.content);
 
     // attach this item as attribute
@@ -99,16 +92,6 @@ BackgroundItem.prototype.redraw = function() {
   // - the item's data is changed
   // - the item is selected/deselected
   if (this.dirty) {
-    // only change content class when needed
-    if (this.data.content === undefined && this.emptyContent == false) {
-      dom.content.className = 'noContent';
-      this.emptyContent = true;
-    }
-    else if (this.data.content !== undefined && this.emptyContent == true) {
-      dom.content.className = 'content';
-      this.emptyContent = false;
-    }
-
     this._updateContents(this.dom.content);
     this._updateTitle(this.dom.content);
     this._updateDataAttributes(this.dom.content);

lib/timeline/component/item/Item.js

@@ -176,8 +176,8 @@ Item.prototype._updateContents = function (element) {
     element.innerHTML = content;
   }
   else {
-    if (!(this.data.type == "background" && this.data.content === undefined)) {
-      throw new Error('Property "content" missing in item ' + this.data.id);
+    if (!(this.data.type == 'background' && this.data.content === undefined)) {
+      throw new Error('Property "content" missing in item ' + this.id);
     }
   }
 };