After creating the tree panel, I set the collapsible property to true. On the page, after clicking on that collapse icon(>>), the tree is collapsed. But when I try to expand it again after collapse, it doesn't expand. On page, the javascript error says "Function Expected". I am totally stuck and need help. Please do help me out. Here is the code which I used to create a TreePanel. After creating this tree, I add it to the viewport.
var tree1 = Ext.create('Ext.tree.Panel', {
title : " ",
xtype : 'treepanel',
store : store,
id : 'tree1',
region : 'west',
height : 300,
width : '19%',
useArrows : true,
rootVisible : false,
collapsible:true,
expand : true,