Device: Nexus 6 (Android 7); Build: Nightly 55.0a1 (2017-05-08); Steps to reproduce: 1. Open the twitter web app and open an external link (some external links open in the browser). 2. Close the tab opened in Nightly (with the web app closed/minimized.). Expected result: Tab is closed, the web app remains closed/minimized. Actual result: The web app from which the tab belonged, re-opens/maximizes. note: It doesn't behave like this on Chrome.

When closing a tab, we're selecting it's parent tab, which in this case happens to be a web app. If we don't want this, I think we could e.g. restrict this to usage of the back button (as opposed to closing a tab from the tabs tray).

[triage] undefined for P1 or P2, we would like to make the call once dale had solution to fix Also NI UX to reconfirm the expected behavior

If we close the opened tab from PWA then back to the web app directly, some use cases may be confusing. For example, if there are many tabs on the tab tray, users close some tabs then still stay in nightly, but close the opened tab from PWA then close nightly and back to the web app. I think this makes users confused. So, my expectation is what you mentioned "Tab is closed, the web app remains closed/minimized", and same as Chrome does.

With GeckoView all of this will be obsolete and need to be reimplemented anyway, but as the change is trivial...

Comment on attachment 8869133 [details] Bug 1363049 - getNextTab() should only use parent tabs of the same type. https://reviewboard.mozilla.org/r/140766/#review144536

Pushed by mozilla@buttercookie.de: https://hg.mozilla.org/integration/autoland/rev/f45828fef374 getNextTab() should only use parent tabs of the same type. r=walkingice

Verified as fixed on Nightly 55 (2017-05-24) Devices: -Asus ZenPad 8.0 Z380KL (Android 6.0.1) -Prestigio Grace X5 (Android 4.4.2) -Huawei Honor 8 (Android 6.0)