Hi Daniel
First, put ServerContrroller.JavaScriptOptions.Debug=True, you might want also to set ServerContrroller.JavaScriptOptions.UseUncompressedFiles=True, but this is not important for this.
When you set ServerContrroller.JavaScriptOptions.Debug=True, the javascript generated is more readable.
Run your application. Inthe browser, hit F12, this will lead you to the development tools.
Check Scripts, the main script, and find the OnStop part. Put a breakpoint there.
But if you want you can send us a test case of what you're doing, or gop to skype id cgdevtools, we make a fast remote session to tell you how its done quicker than type