User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.8b2) Gecko/20050530 Firefox/1.0+ Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.8b2) Gecko/20050530 Firefox/1.0+ All types of installing extensions does not work in such case beside dropping the xpi to the EM window (rather obvious). Reproducible: Always Steps to Reproduce: 1. Choose a page which takes a while to load. 2. Stop it from loading and try to install the extension (even from the partially loaded page) or try to install the extension when the page is not yet fully loaded. Actual Results: The XPInstall dialog does not show. Expected Results: The XPInstall dialog does show.

The relevent code http://lxr.mozilla.org/seamonkey/source/xpinstall/src/nsXPInstallManager.cpp#208

Now that we support whitelisting (in Firefox, but not Suite) we could change the code to check the loading status only if whitelisting is turned off (it's there to prevent abusing install prompts, which have been seen in the wild). *** This bug has been marked as a duplicate of 271567 ***