Reproducible on: Nightly 39.0a1 (2015-03-04), Aurora 38.0a2 (2015-03-04), Beta 37.0b2 (20150302192546), Release 36.0 (20150222232811), Release 35.0.1 (20150122214805). Affected platforms: Ubuntu 14.04 (x64), Mac OS X 10.9.5 - partially, see note (d) below Steps to reproduce: 1. Launch Firefox. 2. Access a website that provides Unity content - (e.g.) http://chromianwars.com/demo/. 3. Right click on the media frame. 4. Switch to a different tab. Switch to a different browser window. Switch to a different workspace by pressing [CTRL] + [ALT] + [←] / [→]. Expected result: Bringing a different tab, window or workspace into focus, dismisses the context menu. Actual result: The context menu can only be dismissed by clicking on the media frame it originated from. Notes: (a) I've installed pipelight in order to view and interact with content that requires the Unity Web Player plug-in. (b) This issue is reproducible with and without e10s enabled. (c) I'll follow up with a regression range as soon as possible, as this might be an older regression, or an external/3rd party issue. (d) On Mac OS X 10.9.5 this bug is only partially reproducible, when switching workspaces, otherwise the context menu has the expected behavior. (e) This is not reproducible on Windows machines.
I'm marking this bug as WONTFIX per bug #1269807. For more information see - https://blog.mozilla.org/futurereleases/2015/10/08/npapi-plugins-in-firefox/