Firefox Extension: Add "Pop out" button on login page

I’m using the Firefox extension on Windows and I use a Yubikey. The current login process for me is:

  1. Type master password
  2. Get message “This browser cannot process U2F requests in this popup window. Do you want to open this popup in a new window so that you can log in using U2F?”
  3. Open new window
  4. Type master password again
  5. Tap Yubikey

Once logged in there’s a button in the top left to “Pop out to a new window”. If this button were present on the log in screen I could open a new window before logging in and therefore only have to type my password once.