Google Chrome Microsoft Edge Windows 10 Home
version 98.0.4758.82 version 98.0.1108.43 version 21H1

If you scroll down the page and hover over any link, the side menu disappears when you return to the top of the page (Figures 1 and 3). The disappearance is also observed in incognito mode (fig. 2).

The phenomenon is detected by scrolling down to the words "Hire a developer" (you can go lower, but not higher). The menu does not change its distorted state until the pointer is moved, but if it was on a left-sidebar item, the state will change when you leave it. The menu items do not disappear smoothly, but in whole lines (first the word Home disappears entirely, then PUBLIC, etc.).

The change can be observed even without authorisation, but it requires removing the top bar (fig. 4) (via developer's tools or by using a standard cross). The selected menu item disappears one by one: first the text and then the background (fig. 5).

Presumably, the minimum page height should be 4814px (matching page). But this is not only true for certain question pages, for example the general question list (50 questions per page) (Fig. 6) or the synonyms page (Fig. 7) are also subject to this change.

It is found that there is a minimum page scrolling speed. If the speed is insufficient, the menu will remain visible. It's also possible to get to a state where you don't have to remove the cursor from the link (fig. 8).

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Figure 1. Side menu disappears Fig. 2. The problem persists even in incognito mode Fig. 3. It is even possible to hover over a link in the same block Fig. 4. Top panel of the unauthorised user
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Figure 5. Intermediate state of disappearance Fig.6. General question list Fig.7. Synonyms page Fig. 8. Interesting result


Laurel was able to repeat the phenomenon on Skeptics Meta using Google Chrome on Mac: https://i.sstatic.net/Ca9x2.png

  • 3
    Unable to reproduce in firefox or chrome.
    – Luuklag
    Commented Feb 10, 2022 at 8:37
  • Are there others who can reproduce that behavior? Maybe those who upvote? Commented Feb 10, 2022 at 14:22
  • @αλεχολυτ This happens to me on an apparently random basis (and not on ru SO). But for some reason the steps here to reproduce it don't show the bug for me.
    – Laurel
    Commented Feb 10, 2022 at 15:02
  • 2
    It's been over a month, but I reproduced it on Skeptics Meta using Google Chrome on Mac.
    – Laurel
    Commented Mar 16, 2022 at 2:25
  • @Laurel this is awesome, thanks for trying. Commented Mar 16, 2022 at 7:45

1 Answer 1


I managed to reproduce it intermittently (on Windows using Chrome, Brave and Opera GX; no repro on Firefox) on different SE sites — the first time I noticed this was before this question was posted.

The code below may help to repro on a specific page, I think the issue is both related to the scroll-up speed and to the page height. Sometimes the bug doesn't happen, so I refresh the page and try again.

Type this once on your browser's console (press Ctrl + Shift + J or Cmd + Shift + J to open the console):

function scrollBug(delay = 0) {
  scrollTo({ top: document.body.scrollHeight, behavior: 'auto' });

  setTimeout(() => {
    scrollTo({ top: 0, behavior: 'smooth' });
  }, delay);

Then just call the function with scrollBug() to test.

It scrolls to bottom immediately, then scrolls up smoothly and the first link on the left sidebar is hidden when the scroll reaches the top of the page.

When I scroll manually, sometimes all links are hidden. Using the script above, only the first one is hidden.

It's worth mentioning that my window.outerHeight is 864px, so the script may not work if your resolution is too different.

  • Thank you very much for your message. I'd just like to point out that your method involves continuous swiping, but a real person with a computer mouse in his hand is unlikely to be able to provide that. I want to point out that I observe the disappearance both when using a touchpad and when using a regular computer mouse (so I didn't specify the source of the input) Commented Feb 10, 2022 at 16:21
  • But it could be a clue. Perhaps it is not the speed of swiping that should be monitored, but its frequency Commented Feb 10, 2022 at 16:27
  • 1
    I know it's different, I just shared this code because it worked to repro the bug on the mentioned page, and maybe it help the developers to debug. I also did a more complex code to simulate scroll-stop-scroll (like a person would do using a mouse), but the results weren't any better. Commented Feb 10, 2022 at 16:28

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