Created attachment 8630344 [details] console Testcase attached. if e10s is disabled, there will be a "drop" throw to console, but there will no when is enabled.
I certainly get "drop" both in e10s and without e10s. Which platform are you using?
(In reply to Olli Pettay [:smaug] from comment #1) > I certainly get "drop" both in e10s and without e10s. > Which platform are you using? I don't understand. I've been checked it with blank profile for about 1 hour... Now I got "drop" too...strange. Windows 8.1 x64 & Firefox 42nightly