Re: On the other hand.
"I too am annoyed by failure-to-paste but I'm at a loss on what to do with the linked code. Do I edit the web page, run it as a script (how?)."
According to the instructions, you need to bookmark the "allow pwpaste" link (which here - Firefox - stores the Javascript itself as the bookmark) and click on that bookmark whenever you're on a page that prevents pasting into the password field.
Looking at the Javascript itself, what it does is identify all the input form elements on the current page and looks for any that are of type 'password'. If it finds any (on a log-in screen there would normally be one) then if there's an 'onpaste' attribute, it's removed - thereby enabling pasting into the password field.
Quite a neat solution (speaking as someone who doesn't really use Javascript so is far from an expert and doesn't know if there's a better way).