Bug 90546 – Scrollbar width is not applied when element hidden

• Component: New Bugs
• Status: RESOLVED FIXED

[Allan Jardine]

I have a function which attempts to calculate the width of a scrollbar by putting two elements on to the page, one inside the other and forcing the inner element to a larger height than the outer which is overflow: auto; Then by subtracting the outer width from the inner we get the scrollbar width.

This works in nearly all applications, apparent from when -webkit-scrollbar styles are applied to the scrolling element, and the element is visibility: hidden (note that if the element is visible, then it works as expected).

Test case with element visible - works as expected: http://sprymedia.co.uk/media/misc/webkit/custom_scroll_visible.html
Test case with element hidden - doesn't work: http://sprymedia.co.uk/media/misc/webkit/custom_scroll_hidden.html

If -webkit-scrollbar styles are not applied, then it will work regardless of visibility.

Tested in WebKit r121825 and shipping Safari 5.1.7 (7534.57.2).

Filed in 'New Bugs' as I'm not sure if this is a Javascript or rendering engine issue.

Created attachment 210584 [details]
Patch

(In reply to comment #1)
> Created an attachment (id=210584) [details]
> Patch

Incase of custom-scrollbars webkit considers the visibility property and incase its hidden doesnot apply the scollbars properties.
Same is not for non-customscrollbars. In either case scrollbar properties are applied.
Behaviour should be same for both since even if element visibility:hidden space is set for that element.

(In reply to comment #1)
> Created an attachment (id=210584) [details]
> Patch

Hi Darin. Can you please review this patch?

[Darin Adler]

I don’t think I have the expertise to review this. Maybe Beth Dakin, Simon Fraser, or Hyatt?

[Simon Fraser (smfr)]

Comment on attachment 210584 [details]
Patch

Seems reasonable.

(In reply to comment #5)
> (From update of attachment 210584 [details])
> Seems reasonable.

Thanks for the review Simon. Anything else needs to be done?

[WebKit Commit Bot]

Comment on attachment 210584 [details]
Patch

Clearing flags on attachment: 210584

Committed r155323: <http://trac.webkit.org/changeset/155323>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

*** Bug 66306 has been marked as a duplicate of this bug. ***