Recently I'm not able to copy a parsed request payload from Chrome DevTools. Button is disabled. I'm able to copy normal POST and GET request but not a parsed JSON payload.
This is huge pain in the ... Anyone know the solution for it?
Came to your question having the same problem.
My solution: Select the text with your mouse pointer and make sure you are not selecting more than the whole content, then try again.
I was selecting more than the contents by triple clicking it and it wouldn't let me copy, probably a bug in chrome.