Now that the helper addon has been updated in bug 574685, we should finish optimizing the experience of testing an addon without the helper addon installed. The optimizations are described in bug 574685, comment 4, to wit: 5. Once the helper addon has been installed and loaded, FD notifies the user that it is proceeding with the testing of the addon via a temporary notification that disappears after several seconds (and thus does not need to be dismissed manually). That notification reads: Now that you have installed the Add-ons Builder Helper, loading the add-on into your browser for testing... 6. FD tells the helper addon to load the addon into the user's browser, and the helper addon does so. Note that there are no page reloads as part of this process, as reloads can lose the user's context on a page (scroll position, unsaved changes, the test request) or require cumbersome additional steps (a prompt about saving unsaved changes, once we add that feature). Instead, the helper addon should notify open FD pages when it is installed and inject the necessary globals into them. And FD pages should start using those globals the moment it receives those notifications.
I created a doc about it as the UX is a bit complicated. https://wiki.mozilla.org/Labs/Jetpack/FlightDeck/Development_Docs/AddonBuilderHelperIntegration
Fixed http://github.com/zalun/FlightDeck/commit/fdafe21bc9c05f01210239b5ceaa7a7fbaa5ca6a Running on http://flightdeck.zalewa.info/