Not able to check SelectAll check box in a grid developed in Ext js

Appu

Hi,

i am using Sahi with Twist and trying to check Select All check box in a page developed in Ext js.
When i try to find the check box its giving me true but when i try to click or check that its giving void.

<div class="x-column-header x-unselectable x-column-header-checkbox x-box-item x-column-header x-unselectable-default x-column-header-align-left x-column-header-first" id="gridcolumn-1178" role="presentation" style="left: 0px; top: 0px; width: 24px; height: 22px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;">
<div class="x-column-header-inner" id="gridcolumn-1178-titleContainer" style="height: 22px; padding-top: 0px;">

<span class="x-column-header-text" id="gridcolumn-1178-textEl"> --this line is what representing the Select All checkbox

So is there any way i can do this?

Aparanji