Bug 787619 shows a case where a media player script expects the plugin to block clicks and because the click-to-play placeholder does not the script thinks you're still seeing the preview image and recreates the plugin.
Created attachment 673569 [details] [diff] [review] Proposed patch
Comment on attachment 673569 [details] [diff] [review] Proposed patch [Approval Request Comment] Regression caused by (bug #): User impact if declined: Unable to click-to-play some plugins Testing completed (on m-c, etc.): Similar patch applied to Firefox Risk to taking this patch (and alternatives if risky): Very low String changes made by this patch: None
Pushed comm-central changeset cb0c2eab4492. https://hg.mozilla.org/releases/comm-aurora/rev/5a3bce57a4be https://hg.mozilla.org/releases/comm-beta/rev/4b325b90838c