This is a long video, 2min, that shows multiple identities working. You'll be able to see Patchfox running this main identity (which is running locally on Patchwork), and I'll open a new tab using another identity. The other identity will be the one running on my Surface Go.
Just be gentle, the Surface Go is a very small machine. It has a Pentium-class CPU and a slow SDD. I haven't used it in a long time, so when I launched Patchwork to make this video, it spent most of it's CPU time scuttling and trying to fetch and index stuff. That makes it less responsive than it usually is. Because of that you'll see that some queries take a really long time, such as fetching the profile information. It is not a fatal flaw that prevents usage, you just need to take it slow, or help me optimise all the queries ;-)
The next step for Patchfox is to add support for go-ssb and browser-ssb. I'm doing that to have a single client that can be used to help developing those servers while still being able to run your main identity simultaneously.