Preferred Choice for Saved Passwords depending on Domain

Hey folks and folkins. I save all my passwords to my firefox. I created a password for privileged access to my firefox at configuration time at some service. Recently (about half a year ago!) I created a new user at the same service (the same domain). The new login was used two times and is now stalled to log-in. It was simply a monitoring user. Each time I visit the domain I get prompted with the monitoring user instead. I can not simply focus the username and select my previous user from the drop-down. Nor does firefox-password learn my preference (which is a good thing, I guess). Nonetheless: I have to delete the username, write the first character of my user and then I can select my password. I find it cumbersome since I do this multiple times a day. Imho there are privacy solutions which could be applied. I don't see any existing options in the UI. Sincerly, Thomas