How do I detect when a safari webplugin loses focus?

I need to be able to detect the browser loses focus in a webkit plugin I wrote. I thought I could implement the webViewUnfocus method from the WebUIDelegate protocol but that's not firing. Does anyone have a pointer to a code snippet for what should be a relatively simple proble开发者_开发技巧m?

The solution to this problem was to setup an observer that watched for NSApplicationDidBecomeActiveNotification and NSApplicationDidResignActiveNotification notifications. This let me cleanup and reinitialize when the app lost and regained focus.