Popup Window for StatusBar Item

I'm building an Application and it needs to have a status bar item and a custom popup window, that popups when the status bar item is clicked.

I know how开发者_JAVA百科 to set up a status bar item and a nsmenu for it, but I need a custom window rather than a nsmenu.

An example for what I'm looking for would be Take Five by the IconFactory

I really hope you have any ideas how I can do it.

Checkout the following example project by Matt Gemmell:
Using MAAttachedWindow with an NSStatusItem

Screenshot: