Comment 2 for bug 1311643

To be more precise, the behavior is different in ff & chromium. For chromium, even when you have a webapp that has been manually installed (which is different than preinstalled) and the user did not actively choose either yes or no (ie the allowed & dontask dconf lists have not been updated w/ this webapp), we show the prompt (in a subsequent session).

FF does not act this way and as soon as the webapp is installed does not prompt anything anymore.

http://bazaar.launchpad.net/~webapps/webapps-greasemonkey/trunk/view/head:/components/unity_webapps.js#L484

vs

http://bazaar.launchpad.net/~webapps/unity-chromium-extension/trunk/view/head:/chromium-extension/background-page.js#L246