This question may have already been asked, but all I could find about it was for Unity.
How am I able to hide a program from the dash? I'm using Dash to Panel in Gnome 18.04, but I don't think that should make a difference. What I'm trying to do is make up Up-Clock not show up in the dash, as I just want it open on my second monitor and not in the dash. Link to same question but for unity: How can I hide a running program icon from the notification bar and Launcher?