STR: 1) bring up the new start screen / start menu 2) click on Firefox result: firefox launches and a window opens 3) bring the start screen back up 4) click on firefox result: a new window opens vs. bringing the previous firefox window to the foreground.

We need to investigate this a little further. Just bringing back the existing window definitely makes sense in tablet mode, but it's unfamiliar in desktop mode.

Gijs, can you explain why you marked this as blocking bug 1173357?

(In reply to (Limited avail. until June 16) Jared Wein [:jaws] (please needinfo? me) from comment #2) > Gijs, can you explain why you marked this as blocking bug 1173357? Likewise, copy-paste fail, but here I meant bug 1170714. :-\

(In reply to Philipp Sackl [:phlsa] please use needinfo from comment #1) > We need to investigate this a little further. Just bringing back the > existing window definitely makes sense in tablet mode, but it's unfamiliar > in desktop mode. Can we just fix this by doing what you implicitly suggest, ie showing an (the most recent) existing window if this happens in tablet mode, and keeping the current behaviour in desktop mode, or do we need something more elaborate than that? The windows default for tablet mode so far is not keeping icons in the taskbar for it, which means I expect people who don't know about task view (and without a keyboard to use alt-tab) might use the start menu/screen to switch apps. The current behaviour is actively harmful to this pattern because when you have an app with multiple windows and close one, the other window doesn't automatically come up. This seems to be by design (or maybe it's just a really obvious bug which MS hasn't solved yet? Not sure...). So the net effect is that if you try to switch to the existing window by hitting the start screen icon, you get a new window in tablet mode, and if you then close that window you're not back at your existing window, which is obviously very confusing.

(In reply to :Gijs Kruitbosch from comment #4) > Can we just fix this by doing what you implicitly suggest, ie showing an > (the most recent) existing window if this happens in tablet mode, and > keeping the current behaviour in desktop mode, or do we need something more > elaborate than that? Yeah, that sounds like a plan :)

Bug 1165321 - focus existing window if Firefox is already open in tablet mode, r?jaws

This depends on the patch in bug 1170522.

Comment on attachment 8624809 [details] MozReview Request: Bug 1165321 - focus existing window if Firefox is already open in tablet mode, r?jaws https://reviewboard.mozilla.org/r/11733/#review10209 Ship It! ::: toolkit/modules/AppConstants.jsm:136 (Diff revision 1) > + get platformVersion() { Since this is only referenced by the function below, I don't think we should make this a separate function and increase the API of AppConstants.

Comment on attachment 8624809 [details] MozReview Request: Bug 1165321 - focus existing window if Firefox is already open in tablet mode, r?jaws Approval Request Comment [Feature/regressing bug #]: win10 tablet mode [User impact if declined]: the icon on the start screen doesn't do what you'd expect in tablet mode [Describe test coverage new/current, TreeHerder]: nope [Risks and why]: reasonably low (nb: depends on bug 1170522) [String/UUID change made/needed]: nope

Comment on attachment 8624809 [details] MozReview Request: Bug 1165321 - focus existing window if Firefox is already open in tablet mode, r?jaws Safe fix with risk isolated to Windows 10 tablet mode. Beta+ Aurora+

Reproduced this issue with Firefox 40 beta 4 on a MS PRO 2 device running Windows 10 64-bit. Confirming the fix for the following builds: - latest Nightly, build ID: 20150722030205; - latest Aurora, build ID: 20150722004007; - Firefox 40 beta 6, build ID: 20150720220238.