As of firefox for linux installed via flatpak into chromebook linux v121.0, Firefox does not copy and paste to or from the clipboard as it was able to do so in previous versions. Copying and pasting doesn't generate an error or give a message, it simply doesn't paste anything to the destination as if the copy had failed. I am able to copy from a chromeOS app and paste into Firefox. Other Linux apps are still able to open Firefox when a link is clicked. I cannot copy from Firefox (copying text from the page or copying from the address bar) into the clipboard and paste it elsewhere. I've tried uninstalling and reinstalling, tried erasing the linux container entirely and reinstalling, to no avail. Let me know if I can help provide more information, troubleshooting help, or if you would like help testing fixes.