Add "Run only one copy of the application" option.

[EDSln]

Is your feature request related to a problem? Please describe.
Now, if you launch Supermium again when it is running, the second copy of the program will be launched.

Describe the solution you'd like
This behavior is not always necessary, so we need an option that would open a new tab like in Firefox or simply do nothing when launching it again.

Describe alternatives you've considered
There is no way to do this in a standard way, you can only do it using cmd.

[XakerTwo]

just for info: it not run second copy, it's just open new window, like Ctrl+N do. Chromium, internally, on normal flow, not allow multiple instance of browser. there only one root process and all other is just child "containers" for certain tab/window/service, served by the root process

neutral to suggestion

[EDSln]

Technically that's true, but to the user it's a lot of running browsers, and whether they share the same underlying process or not is irrelevant.