Help with controlling visible contexts in the manager tree [Updated]

switch ($modx->event->name) {
    case 'OnManagerLoginFormPrerender': /* if you want to add custom scripts, css, etc, register them here */

  		$results  = $modx->query("SELECT * FROM modx_context WHERE modx_context.key NOT IN ('mgr')");
		$numItems = $modx->getCount('modContext', array('key:NOT IN' => array('mgr')));
		$i        = 0;

		while ($r = $results->fetch(PDO::FETCH_ASSOC)){
		  if(++$i === $numItems){
			$listContext .= "['" . $r['key'] . "', '" . $r['name'] . "']"; // NO comma at the end of the array.
		  }else{
		  	$listContext .= "['" . $r['key'] . "', '" . $r['name'] . "'],";
		  }
		}

		// Define the model for website
		$script = "<script type='text/javascript'>
		  Ext.onReady(function() {

			  /* disable shadows for the combo-list globally, saves a few dom nodes as it's not used anyways */
			  Ext.form.ComboBox.prototype.shadow = false;
			  /* replaces the default img tag for the combo trigger with a div to make the use of iconfonts with :before possible */
			  Ext.override(Ext.form.TriggerField, {
				  // this is the exact method from the source code, just the triggerConfig is modified to not use an img tag
				  // We cannot override the prototype Ext.form.TriggerField.prototype.triggerConfig because we loose the option to add a custom triggerClass
				  onRender: function(ct, position){
					  this.doc = Ext.isIE ? Ext.getBody() : Ext.getDoc();
					  Ext.form.TriggerField.superclass.onRender.call(this, ct, position);
			  
					  this.wrap = this.el.wrap({cls: 'x-form-field-wrap x-form-field-trigger-wrap'});
					  this.trigger = this.wrap.createChild(this.triggerConfig ||
							  {tag: 'div', cls: 'x-form-trigger ' + (this.triggerClass || '')});
					  this.initTrigger();
					  if(!this.width){
						  this.wrap.setWidth(this.el.getWidth()+this.trigger.getWidth());
					  }
					  this.resizeEl = this.positionEl = this.wrap;
				  }
			  });

			  Ext.namespace('Ext.websitedata');
		  
			  Ext.websitedata.websites = [" . $listContext . "];

				  // simple array store
				  var store = new Ext.data.ArrayStore({
					  fields: ['context', 'name'],
					  data : Ext.websitedata.websites // from namespace data
				  });

				  var combo = new Ext.form.ComboBox({
					  store: store,
					  displayField:'name',
					  typeAhead: true,
					  mode: 'local',
					  forceSelection: true,
					  triggerAction: 'all',
					  emptyText:'Select a website...',
					  selectOnFocus:true,
					  hiddenName: 'cntxwebsite',
					  valueField: 'context',
					  applyTo: 'local-websites'
				  });
			});
		</script>";

		$modx->event->output($script);

	break;
	case 'OnManagerLoginFormRender':

 		$fields = '<div class="x-form-item login-form-item" style="padding-top: 17px;">
					<label for="local-websites">Website</label>
					  	<input type="text" id="local-websites" value="" readonly="" style="width: 368px;"/>
        		   </div>';

		$modx->event->output($fields);

	break;
	case 'OnManagerLogin':

		$profile = $user->getOne('Profile');

		$modx->log(modX::LOG_LEVEL_ERROR, "You have logged in with: " . $_POST['cntxwebsite'] . " Your user name is: " . $_POST['username'] . " Session contexts: " . print_r($user->toArray()));

  		$results  = $modx->query("SELECT * FROM modx_context WHERE modx_context.key NOT IN ('" . $_POST['cntxwebsite'] . "','mgr')");

		while ($r = $results->fetch(PDO::FETCH_ASSOC)){

          $resource =  $modx->getObject('modResource',array('context_key' => $r['key']));

		  $user->removeSessionContext($r['key']);
		}


		/*$script = '<script type="text/javascript">
					  var tree = null;
					  Ext.onReady(function() {
						var tree = Ext.getCmp("modx-resource-tree");
						if (tree && tree.rendered) {
							tree.refresh();
						}
					  });
				  </script>';*/


	break;
}