If you drag text onto a Firefox window, it interprets that text as a URL and goes to that page. This is a problem because the only time I drag and drop text onto a Firefox windows is a password from my password manager. If I slightly miss the text box, it interprets the password as a URL and tries to go to it. This (a) Does a DNS lookup of the password. As there usually won't be a valid extension, I expect this only gets as far as my router, but it's still not ideal. (b) The page I was on has now gone, replaced with the "Couldn't connect to server" page, so I need to start again. Usually this is just a login page, which isn't a massive issue, but if it's a registration page I lose all the data I'd entered on that page, and even if it is just a login page, some badly implemented sites can lose information if you step out of the workflow.