To quote the user on Wikimedia Commons: "I usually use the "tab" key on the keyboard to navigate the form on MediaWiki's Special:Upload page. One issue I have is that now, when I want to get from the "permission" field to the categories, I have to "tab" my way through the entire special chars menu (or of course, use the dreaded "cursor"). It would be neat if the "tab" could skip the special chars on its way down towards the "upload" button."
I agree with the user. This can be easily done by setting "tabindex" property of the upload field.