There are sites which prevent any password manager to fill in credentials, so the usual way to go is to copy paste them into the user/pass boxes.
It would be pointless to have this option globally but each of the saved login entries could have an option - a checkbox, that when marked, would allow to copy the password into the clipboard automatically so we would use it for the very few sites that prevent filling credentials.
So all we had to do is to enter the user name or mail, which is easy and then ctrl+v. Currently it is done by clicking on extension icon, then clicking on copy password, then clicking to password box and then finally to ctrl+v… When we need to log in very often to such sites this gets old. It’s still better then having no password manager but the experience would be so much nicer if I just could do the last step.
Of course, by default would be copied the password from login that is up on the list (the default one, the last used). Additionally, when we would choose the one below and click on it, it would also copy password to clipboard so if the credential fill hadn’t work, we would still have easy way to use the password.
This could come with warning (on the option page) that this may be a security whole, but given the fact that this option would be off by default and turned only for few pesky sites, the risk is minimized but the user should still be aware that it’s potentially risky. Open source is about giving a choice and user must take responsibility in its own hands.