Yeah, sorry about that, at the moment it's ignoring .jars. I think I'll take that bit out. Zippy has the code to package your .jar for you, it's commented out in the current version, but I plan to make it an option.
I should point out that having a chrome .jar is no longer best-practice, in fact AMO will warn you if you have one.
The "Create XPI" menuitem is not to be found in the context menu for extensions in the "Recent Updates" tab of the Add-ons Manager. In the "Extensions" tab it is present, at the very bottom under a separator.
I've been using your add-on for over a year with a number of Firefox versions. Never had any compatibility problems as long as the browser was up-to-date. It saved me lots of time and I keep using it. Keep up the good work.
It seems like it's not working on Fx 9.0.1 even though it says it installed. There is not an added option like there used to be in Fx ver 3. It was good while it lasted. I restarted a few times to double check too.
That's OK because I started to save all my xpi's manually now anyway as I try new ones.
I gave it 5 stars because when it did work it was excellent
It would be a great step forward if more than one (or all, actually) add-ons could be selected and wrapped into a single XPI. Add-ons portability from machine to machine would be greatly improved this way.
This is a very convenient tool that fills a few voids in FF. It could potentially fill the void of Extension Manager Extended (abandoned) as well. Please consider providing the extension ID and location within the Add-ons Manager view, eliminating the need to right click and bring up a new page, unless an XPI creation is needed. Thanks for providing this extension!