SDL copy and paste

I’m trying to fix Unreal’s copy and paste bug on Linux that pops up, whenever trying to copy with a right click menu. Their copy function reaches the sdl call, and for whatever reason nothing is in the clipboard for pasting. I have a feeling it has to do with how Epic is creating submenus. (ctrl + c and ctrl + v work properly) So, what I’m asking is how does copy and paste work in SDL? Which objects need to be present for successful paste?