(EDIT: maybe this is a bug, and should go on GitHub.)
I just installed
slack, then re-booted. Now, when I run Chromium, it shows up as Slack. Screenshot:
As you can see, I have only one window open, and it shows up as Slack.
Now because I have Chromium open, I can’t open the actual Slack app, because it thinks I already have Slack open.
So if I quit “Slack” (Chromium), then I start “Slack” instead of “Chromium”, then it’ll open the actual Slack app, but if I then open Chromium, it’ll open a new Chromium window still under Slack!
This screenshot shows both Slack and Chromium windows under “Slack” in the alt-backtick window switcher:
This screenshot shows both Chromium and Slack windows in the Activities overview, but as you see in the task bar there is only “Slack” running: