fix on panels css in left panel

frontend-js/src/main/js/gui/leftPanel/LeftPanel.js

@@ -155,6 +155,7 @@ LeftPanel.prototype.addTab = function(params, navElement, contentElement) {
 
   var contentDiv = document.createElement("div");
   contentDiv.style.height = "100%";
+  contentDiv.className = contentClass;
   contentDiv.id = tabId;
 
   contentElement.appendChild(contentDiv);