While testing Tunein app on desktop (PC ONLY) it was discovered that after download, the app can be launched multiple times from Marketplace. Each launch (via MP's open button) will open a new instance of the app. Actual behavior: Pressing the "open" button in Marketplace after downloading the app will open a new instance of the app. Although this is great when you want to listen to multiple songs at once, I do not suspect this is intentional behavior. Expected behavior: If application is already open, pressing the "open" button in MP should cause focus on the open app, rather than an additional launch.
@Nick - Can you take a look at this bug and provide a comment below?
Confirming that this isn't reproducible in OSX. Let's see if this is reproducible with packaged apps other than tuneIn on windows, to see if it's only applicable to TuneIn, or all of Windows.
Harald just confirmed that this isn't limited to TuneIn.
We could check to see if a process is already running here . Let's see what Myk thinks; Myk, should we not allow Windows to open multiple instances of the same app, or make OSX/Linux able to open multiple instances?  https://dxr.mozilla.org/mozilla-central/source/webapprt/win/webapprt.cpp
(In reply to Nick Desaulniers [:\n] from comment #6) > We could check to see if a process is already running here . Let's see > what Myk thinks; Myk, should we not allow Windows to open multiple instances > of the same app, or make OSX/Linux able to open multiple instances? The runtime is actually opening a new window in the existing process, not starting a new process. That is also what Firefox does on Windows when you invoke it while it's already running (try double-clicking the Firefox icon in File Explorer while the app is running), so the runtime may be inheriting that behavior. Internet Explorer also does this, and Firefox may have copied its behavior on Windos. But Windows Media Player does not; instead, it activates the app and focuses the existing window. I looked at the UX Guidelines for Windows 7/Vista <https://www.microsoft.com/en-us/download/details.aspx?id=2695> as well as Windows Universal Platform <https://msdn.microsoft.com/en-us/library/windows/apps/hh465424.aspx>, but I didn't find any guidance on this question (although these documents are quite voluminous, and I might have missed it). In any case, I think users are going to expect that invoking the app returns them to its existing window, if it's already running, and we should change the runtime to behave that way.
> Marketplace apps no longer run on computers with Firefox as of Firefox 48 for Windows, Mac OS X, and Linux. For more information about the change, see Firefox Marketplace Apps Stop Working on Firefox 48+ for Windows, Mac, and Linux. https://support.mozilla.org/en-US/kb/marketplace-apps-firefox-desktop Invalid.