Open Firefox two instances version 49<=53

[truefriend-cz]

If copy user.js to profile folder and run firefox then run two instances browser.
Any solution?

[nodiscc]

https://github.com/pyllyukko/user.js#known-problems-and-limitations:

Clearing open windows on Firefox exit causes 2 windows to open when Firefox starts https://bugzilla.mozilla.org/show_bug.cgi?id=1334945

Set privacy.clearOnShutdown.openWindows to false

[Anyon3]

Got the same problem, I applied the solution of nodiscc, it fixed it.

Thanks

[pyllyukko]

I think this issue is covered from our side with #289. Hopefully Mozilla will fix this soon.