I wish the bug where the copy option is randomly greyed out even though there is text to copy got finally fixed. It's been driving me insane.
Worst case, if there is bizarre breakage due to frameworks that reinvent text boxes, have a keyboard shortcut or menu item to type the clipboard contents at 300 characters per minute.
https://addons.mozilla.org/en-US/firefox/search/?q=enable%20...
Specifically: Absolute Enable Right Click & Copy
I would prefer of course that the underlying issue get resolved, but in lieu this has been an excellent workaround for my needs.