Codehooligans.com: Disable WordPress Plugins update indicator for inactive plugins

codehooligans-disable-wordpress-plugins-update-indicator.php

function update_active_plugins($value = '') {
	/*
 	The $value array passed in contains the list of plugins with time 
	marks when the last time the groups was checked for version match
	The $value->reponse node contains an array of the items that are 
	out of date. This response node is use by the 'Plugins' menu
	for example to indicate there are updates. Also on the actual 
	plugins listing to provide the yellow box below a given plugin 
	to indicate action is needed by the user. 
 	*/
	if ((isset($value->response)) && (count($value->response))) {

		// Get the list cut current active plugins
		$active_plugins = get_option('active_plugins');		
		if ($active_plugins) {
			
			// 	Here we start to compare the $value->response 
			//	items checking each against the active plugins list. 
			foreach($value->response as $plugin_idx => $plugin_item) {

				// If the response item is not an active plugin then remove it. 
				// This will prevent WordPress from indicating the plugin needs update actions. 
				if (!in_array($plugin_idx, $active_plugins))
					unset($value->response[$plugin_idx]);
			}
		}
		else {
			 // If no active plugins then ignore the inactive out of date ones. 
			foreach($value->response as $plugin_idx => $plugin_item) {
				unset($value->response);
			}			
		}
	}	
	return $value;
}
add_filter('transient_update_plugins', 'update_active_plugins');	// Hook for 2.8.x
//add_filter( 'option_update_plugins', 'update_active_plugins');	// Hook for 2.7.x