Steps to reproduce:

• Install https://addons.mozilla.org/firefox/downloads/file/4282580/groupspeeddial-25.2.xpi
• Restart Firefox
• Remove the extension

Actual results:

Firefox closes itself.

Expected results:

Firefox should replace you custom new tab with Firefox Home.

When an extension is uninstalled, all tabs associated with the extension are closed. We don't do anything special to keep the window or even Firefox around when this happens.

A work-around for users is to open Firefox after it has quit, and/or open a different tab/window before uninstalling (e.g. a private browsing window).

Note: some pages on the web can close themselves via window.close(). When that page is the only tab, that also causes Firefox to quit. Test case:

1. Visit example.com as the only tab.
2. Open the devtools, run onclick = () => window.open("/")
3. Click inside the page, which opens example.com in a different tab.
4. Close the original tab from step 1.
5. Open the devtools in the only tab (from step 3) and run window.close().

Result is that Firefox quits.