title: Getting disabled checkboxes in Grid for a custom admin module in Magento
body: <p>I am working on a custom module in magento admin that uses the ‘sales/order_grid_collection’ class to show the grid of all orders. The grid appears fine.</p>
  
  <p>However, the first column of the grid is of ‘increment_id’, unlike the actual orders grid where the first column has checkboxes for mass action. I am getting this in spite having copy-pasted almost all the code for the _prepareColumns method from the original order module.</p>
  
  <p>So I tried adding a first column of checkboxes manually inside the _prepareColumns method as follows</p>
  
  <pre><code>$this-&gt;addColumn('order_id', array(
           'header_css_class' =&gt; 'a-center',
           'header'    =&gt; Mage::helper('sales')-&gt;__('Assigned'),
           'type'      =&gt; 'checkbox',
           'width' =&gt; '20px',
           'field_name' =&gt; 'orders[]',
           'align'     =&gt; 'center',    
           'renderer' =&gt; new Mage_Adminhtml_Block_Widget_Grid_Column_Renderer_Checkbox(),
           'index' =&gt; 'order_id'           
  ));
  </code></pre>
  
  <p>Upon doing this, the chekboxes do appear but they are disabled.</p>
  
  <p>What am I missing here ?</p>
  
  <p>Thanks</p>