I'm helping my grandma start using a computer,she has trouble understanding when her double clicks are registered with the OS and often ends up clicking more times that necessary.Since the only shortcuts she use are 5 Firefox bookmarks in her Windows desktop, sometimes she ends up with 3 Firefox instances with, say, 2 or 3 tabs per instance, all for the same website.
So I was wondering if there's any browser/extension (for Windows, preferably) that supports any mode of unique-instance-and-tab, so she doesn't have trouble with this.
Having an option to "force-open" a second tab/instance would be a plus, but the default behavior should be to use just one tab in a unique window/instance.
Hacks and "complex" setups are not a problem, the important point is to have it really simple for using.