Scrollbar partially inactive in ChatGPT web when logged out

Bug

What happened, and what did you expect?

Reproduction

Hello,

I have noticed a reproducible scrollbar issue in the ChatGPT web interface when logged out.

Observed behavior

  • The issue occurs when using ChatGPT while logged out.
  • I have reproduced it with both Firefox and Microsoft Edge.
  • When logged in, the scrollbar works normally.
  • When logged out, there is a fixed grey area at the bottom of the vertical scrollbar track.
  • This grey area is completely inactive: mouse clicks have no effect there.
  • If I click slightly above the grey area, still on the scrollbar track, the scrollbar works normally.
  • The inactive grey area appears to intercept mouse input.

See the attached screenshot. The grey/inactive area is clearly visible at the bottom of the scrollbar track.

DevTools observation

Using Firefox DevTools, I inspected this area.

The element identified there is:

footer.wm-desktop-detailFooter

Its CSS includes:

position: absolute;
z-index: 1;

This appears to be a possible overlay/interception of pointer events over the lower part of the scrollbar.

The issue is particularly interesting because the scrollbar works immediately when clicking just above this grey area.

I have reproduced the problem in more than one browser, while the problem disappears when logged in.

I believe this may be worth investigating as a web UI bug, especially if other users are experiencing the same behavior.

Thank you.