The links to files at the top of a code review page go to an anchor with the same name as the path to the file.
Problem is, this anchor occurs twice in the HTML -- once at the top, once at the bottom.
Opera happens to choose the bottom one, so clicking on any file link will invariably take me to the bottom of the review for that file. Firefox presumably chooses the top. To remove the ambiguity, the one at the bottom should probably be removed.