I’ve recently been working on a GUI extension for 2011. Following the great work being done in the Power Tools project I refactored my server-side functionality in to a Model. This brings my extension in line with the approach used by our R&D guys when they create extensions. It also, apparently, broke SiteEdit in my environment
Investigation
It didn’t take much figuring out the cause of my problem – the only change to my environment between SiteEdit working and the problem appearing was the refactoring of my extension. A quick tweak of the configuration to disable it had SiteEdit working again. I launched Firebug to see if It would highlight anything untoward, and it was clear to see that SiteEdit was trying load my Model!
I thought this was strange, but a quick email to R&D confirmed that this was the expected behaviour. Apparently SiteEdit loads the CME in the background when it starts.
Solution
The solution was a a simple one in the end – when you configure your Model’s virtual directory in CME website in IIS, you need to make sure you also do it in the SiteEdit website. It wasn’t clear to me whether it’s good practice to do the same for your Editors, but I didn’t and it wasn’t an issue for me.