Modify contents of Firefox download dialog from add-on kit

Question

I'd like to be able to add an option to the download dialog that pops-up in Firefox when starting a file download. Is it possible to do so using the new add-on SDK or do I have to do it the old way?

edit: Obviously, if the new option is selected, I need a way to know it and execute code based on it.

Answer 1

That's something you would use XUL overlays for. I guess that the dialog you are talking about is chrome://mozapps/content/downloads/downloads.xul - the download manager. AFAIK doing this isn't possible with the Add-on SDK, it only provides the most common UI integration points. You could create a traditional extension however, it can overlay any dialog.