1944518 - app.powerbi.com - Unable to scroll vertical and horizontal overflow elements, scroll bar missing

Status: ASSIGNED

(Web Compatibility :: Site Reports, defect, P3)

Description

[Calin Tanase]

Environment:
Operating system: Mac OS X 10.15
Firefox version: Firefox 134.0/136

Steps to reproduce:

1. Go to https://app.powerbi.com/view?r=eyJrIjoiYmVjMjViZjgtYTI2NS00NzcxLWFiMDQtYjM5OGI2YWQzMDUwIiwidCI6IjA0MmQ3NzA5LWMwNWItNGRlZC1hYjg4LTc0NDMwYzU0YmZlNyJ9
2. Observe the page.

Expected Behavior:
Vertical and horizontal overflow elements have a scroll bar.

Actual Behavior:
Vertical and horizontal overflow elements do not have a scroll bar.

Notes:

• Reproduces regardless of the status of ETP
• Reproduces in firefox-nightly, and firefox-release
• Does not reproduce on Windows 10
• Does not reproduce in chrome

Created from https://github.com/webcompat/web-bugs/issues/146089

Comment 1

[Calin Tanase]

Attachment: FF vs Chrome.png

Comment 2

[Sky Schubert [:skyschub]]

This seems to be UA dependent? Works for James on Linux, works with Chrome Mask, broken with the default macOS UA

Comment 3

[Daniel Holbert [:dholbert]]

(In reply to Dennis Schubert [:denschub] from comment #2)

This seems to be UA dependent? Works for James on Linux, works with Chrome Mask, broken with the default macOS UA

Confirmed. It's slightly more subtle than just UA-sniffing, though, because I still get expected results on linux even when using Firefox-for-macOS UA string.

I think they also check "is your navigator.platform macOS". I strongly suspect this is the relevant JS:

        if (
          [...conditions that don't matter...] ||
          d.macosx &&
          !d.webkit
        ) return !1;

https://content.powerapps.com/resource/powerbiwfe/scripts/reportembed.externals.bundle.min.40263725b44d9c8afdc6.js

d.macosx and d.webkit are defined in the same file, here:

      macosx: /mac/i.test(navigator.platform),
[...]
      webkit: /webkit/i.test(navigator.userAgent) &&
      !/edge\/\d+/i.test(navigator.userAgent)

Anyway: still seems like we can avoid this by spoofing a Chrome UA on macOS. I imagine the site is trying to avoid having their scrollbars overlap with overlay-scrollbars, or something along those lines, but the result ends up being completely broken unfortunately.

Comment 4

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1944518 - add a MacOS-only UA override for app.powerbi.com to unhide their scrollbars; r?denschub

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/93ea8b3b2c3a
add a MacOS-only UA override for app.powerbi.com to unhide their scrollbars; r=denschub,webcompat-reviewers

Comment 6

[Serban Stanca [:SerbanS]]

https://hg.mozilla.org/mozilla-central/rev/93ea8b3b2c3a

Comment 7

[Thomas Wisniewski [:twisniewski]]

The page is gone now; I get this when I visit:

This content isn't available.
Learn more about Power BI.

However, we do still seem to need an intervention for PowerBI, and they are using webkit-scrollbar CSS without the standards-compliant variants for scrollbar styling, based on what I see at https://app.powerbi.com/view?r=eyJrIjoiN2U3NGMyNWEtZTAxNS00MzVhLWExNmMtOThhZjdiYjQ4MWNkIiwidCI6IjEyNGU2OWRiLWVmNjUtNDk2Yi05NmE5LTVkNTZiZWMxZDI5MSIsImMiOjl9

I'll update the intervention appropriately.

Comment 8

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1944518 - update our webcompat intervention for app.powerbi.com to hide scrollbar styling on Mac; r?denschub

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/409a8dbff613
https://hg.mozilla.org/integration/autoland/rev/f67c0e7010c5
update our webcompat intervention for app.powerbi.com to hide scrollbar styling on Mac; r=webcompat-reviewers,ksenia

Comment 10

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/f67c0e7010c5