Image data not preserved on clipboard after application closes (linux x11)

[t-lock]

I am not sure if this is expected behavior on my platform or not, but I am experiencing the following:

1. When writing text data to clipboard, I can exit the application with os.Exit(0) and still retain the text on the system clipboard
2. When writing png img data to clipboard with no other changes, the clipboard is emptied when the application closes
3. When leaving the application running in the background with no other changes, I can paste png data around my system. As soon as I close the application, I can no longer paste the image

I am on Linux X11, distro is Pop OS <-- Ubuntu <-- Debian.

As a fallback, I am leaving my application running in the background until I can detect that the clipboard has been overwritten, but I just close my GUI window, so the user experience mimics "I got my screenshot on the clipboard and the screenshot application has now closed, but I can go paste this somewhere".

Cheers!