While building my test environment, I discovered more about my issue. It looks like it's a different issue than zybna is having. It turns out that there is a bug in spectrwm that doesn't display minimized windows. Spectrwm also doesn't have a system tray, so there's no visual indication that Ksnip is running, and no way to interact with it. Ksnip is starting, and it is starting on the correct display server, but it's starting minimized (and the spectrwm bug prevents me from seeing and correcting this.)

I wrote a bash script to unminimize Ksnip after launch. I now launch it with script.
ksnip-unminimize-wrapper.tar.gz

Starting minimized appears to be a Ksnip issue because this also happens in other window managers. Is this intended?

The script I wrote fixes the issue for me, so it might not need your attention unless this issue affects other users as well.

If you'd like to pursue the underlying "starting minimized" issue, I've uploaded the test vm I used to troubleshoot this here. It's using JWM (another window manager with this issue) instead of spectrwm because JWM is a lot simpler to work with and gives a visual indicator of minimized windows and a system tray. The username is arch and the password is arch. Ksnip is already installed from source using the latest version. You can click the start menu, then terminal, and then run Ksnip from the terminal to see what happens.

Thanks for the great software! I use Ksnip for it's excellent annotation features, and this workaround means I can continue using it.

Originally posted by @connorhodes in #575 (comment)