dot/.local/share/gnome-shell/extensions/launch-new-instance@gnome-shell-extensions.gcampax.github.com/extension.js

/* exported enable disable */
const AppDisplay = imports.ui.appDisplay;

let _activateOriginal = null;

function enable() {
    _activateOriginal = AppDisplay.AppIcon.prototype.activate;
    AppDisplay.AppIcon.prototype.activate = function () {
        _activateOriginal.call(this, 2);
    };
}

function disable() {
    AppDisplay.AppIcon.prototype.activate = _activateOriginal;
}