Sticky vote button problems on Stack Overflow

[Sir-Cumference]

Installed Version: 2.0.29 Environment: Tampermonkey

Current Behaviour

On this question, the post will shift once you scroll down far enough for the buttons to be sticky. This is because it has over 10k upvotes. I can't really fix this without causing the vote buttons to lag (à la the MutationObserver problem), but I hopefully improved it with the code below.

Also, you can see that the buttons will be covered by the topbar:

Here's the solution I wrote (though I don't have enough rep to check if it works in the review section on SO):

stickyVoteButtons: function() {
    // Description: For making the vote buttons stick to the screen as you scroll through a post
    //https://github.com/shu8/SE_OptionalFeatures/pull/14:
    //https://github.com/shu8/Stack-Overflow-Optional-Features/issues/28: Thanks @SnoringFrog for fixing this!

    stickcells();
    $(document).on('sox-new-review-post-appeared', stickcells);

    $(window).scroll(function() {
        stickcells();
    });

    function stickcells() {
        var $votecells = $('.votecell');

        $votecells.each(function() {
            var $topbar = ($('.so-header').length) ? $('.so-header') : $('.topbar'),
                topbarHeight = $topbar.outerHeight(),
                offset = $(".review-bar").outerHeight();

            if ($topbar.css('position') == 'fixed' && !sox.location.on('/review'))
                offset += topbarHeight;
            else
                offset += 5; //For some reason I have to add the bottom margin of ".review-bar"

            var $voteCell = $(this),
                $vote = $voteCell.find('.vote'),
                vcOfset = $voteCell.offset(),
                scrollTop = $(window).scrollTop(),
                realHeight, endPos;

            $voteCell.css('min-width', Math.floor($vote.width()));

            if ($vote.length && $vote.children().last().length && $voteCell.next().length) { //These values strangely alternate between existing and not existing. This if statement insures we only get their values when they exist, so no errors.
                realHeight = $vote.children(':not(:hidden, .message-dismissable)').last().offset().top + $vote.children(':not(:hidden, .message-dismissable)').last().height() - $vote.offset().top; //Get the original height; the difference between the last child and the first child's position
                endPos = $voteCell.next().offset().top + $voteCell.next().height() - 51; //I think a bit above the end of the post (where the "edit", "delete", etc. buttons lie) is a good place to stop the stickiness.
            }

            $voteCell.on('DOMNodeInserted', function() { //Fix dismissable message boxes, like "Please consider adding a comment if you think this post can be improved." when downvoting
                $vote.find('.message-dismissable').css({
                    position: "absolute",
                    "white-space": "nowrap"
                })
            })

            if (vcOfset.top + realHeight < endPos - 25 && vcOfset.top < scrollTop + offset) { //Left condition is to get rid of a sticky zone on extremely short posts. Right condition allows stickiness unless we're above the post.
                if (scrollTop + offset + realHeight < endPos) { //Allow stickiness unless we've scrolled down past the post.
                    $vote.css({
                        position: 'fixed',
                        top: offset
                    });
                } else {
                    $vote.css({
                        position: 'absolute',
                        top: endPos - realHeight //Leave the button at its bottommost position
                    });
                }
            } else {
                $vote.removeAttr('style'); //Remove any stickiness
            }
        });
    }
},

---

Features Enabled

["Appearance-addAuthorNameToInboxNotifications","Appearance-dragBounty","Appearance-fixedTopbar","Appearance-isQuestionHot","Appearance-markEmployees","Appearance-metaChatBlogStackExchangeButton","Appearance-metaNewQuestionAlert","Appearance-spoilerTip","Appearance-standOutDupeCloseMigrated","Appearance-unspoil","Comments-autoShowCommentImages","Comments-commentReplies","Comments-commentShortcuts","Comments-moveBounty","Comments-showCommentScores","Comments-hiddenCommentsIndicator","Editing-editReasonTooltip","Editing-enhancedEditor","Editing-titleEditDiff","Editing-inlineEditorEverywhere","Editing-downvotedPostsEditAlert","Flags-flagOutcomeTime","Flags-flagPercentages","Flags-flagPercentageBar","Sidebar-linkedToFrom","Chat-replyToOwnChatMessages","Voting-betterCSS","Voting-grayOutVotes","Voting-stickyVoteButtons","Voting-disableOwnPostVoteButtons","Extras-alwaysShowImageUploadLinkBox","Extras-parseCrossSiteLinks","Extras-quickAuthorInfo","Extras-hideCertainQuestions","Extras-showMetaReviewCount","Extras-copyCode"]

[shu8]

@Sir-Cumference thanks again for the fix! :) We'll get this added in ASAP :)

(sorry for the late reply as well!)

[shu8]

@Sir-Cumference done in dev 2.0.31! :)

(sorry this took sooooo long!)