930771 - Defect - Hover scrollbars leave white band after fading out

Status: VERIFIED FIXED

(Firefox for Metro Graveyard :: Firefox Start, defect, P2)

Description

[Jim Mathies [:jimm]]

str:

open about:start
move your mouse
wait for the scrollbar to fade out

result: white band in place of the scrollbar

Comment 1

[Matt Brubeck (:mbrubeck)]

Not just on the start tab - you can also see this on any page with scrollbars

Comment 2

[Stephen A Pohl [:spohl]]

I think I know what's going on here. In nsNativeThemeCocoa.mm [1] we specifically handle the NS_THEME_SCROLLBAR case when overlay scrollbars are turned on. This is necessary to calculate negative margins [2] for the scrollbars. This seems to be missing on Windows [3], which results in white bands.

[1] http://mxr.mozilla.org/mozilla-central/source/widget/cocoa/nsNativeThemeCocoa.mm#2849
[2] http://mxr.mozilla.org/mozilla-central/source/layout/xul/base/src/nsScrollbarFrame.cpp#175
[3] http://mxr.mozilla.org/mozilla-central/source/widget/windows/nsNativeThemeWin.cpp#2205

Comment 3

[Stephen A Pohl [:spohl]]

Attachment: Patch

Comment 4

[Jim Mathies [:jimm]]

Comment on attachment 829542 [details] [diff] [review]
Patch

Review of attachment 829542 [details] [diff] [review]:
-----------------------------------------------------------------

::: widget/windows/nsNativeThemeWin.cpp
@@ +2320,5 @@
>  
> +    case NS_THEME_SCROLLBAR:
> +    {
> +      if (nsLookAndFeel::GetInt(nsLookAndFeel::eIntID_UseOverlayScrollbars) != 0) {
> +          aResult->SizeTo(20, 20);

where do these dimensions come from?

Comment 5

[Stephen A Pohl [:spohl]]

Attachment: Patch

Oh, I mistook NS_THEME_SCALE_THUMB_VERTICAL a few lines above for NS_THEME_SCROLLBAR_THUMB_VERTICAL and thought we're already hardcoding these values. We should just get these from the system and they are actually (21, 21) instead of (20, 20). I think this might be a bug because it causes us to draw a 1px white line above the horizontal scrollbar (and to the left of the vertical scrollbar), but this is probably out of the scope of this particular bug here.

Comment 6

[Stephen A Pohl [:spohl]]

Attachment: Patch

Forgot 'hg qrefresh'

Comment 7

[Stephen A Pohl [:spohl]]

Attachment: Patch

Now respecting the 80 character limit. Sorry about the bugspam.

Comment 8

[Stephen A Pohl [:spohl]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/9bee8f4c3fbd

Comment 9

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/9bee8f4c3fbd

Comment 10

[Manuela Muntean [Away]]

I can still reproduce this issue, while testing for iteration #19, with latest Nightly from 2013-12-01 on Win 8 64-bit.

If I go to https://mail.google.com/intl/en/mail/help/about.html then dismiss the navbar and click somewhere on the page, the scrollbar will eventually fade out and a white band will replace it.

Comment 11

[Stephen A Pohl [:spohl]]

(In reply to Manuela Muntean [:Manuela] [QA] from comment #10)
> If I go to https://mail.google.com/intl/en/mail/help/about.html then dismiss
> the navbar and click somewhere on the page, the scrollbar will eventually
> fade out and a white band will replace it.

Hmm, this works fine for me on today's Nightly (2013-12-02) on Win8 64-bit metro mode. Is there anything else I need to do to reproduce this?

Comment 12

[Manuela Muntean [Away]]

Attachment: 2 screenshots.zip

I've retested this with today's Nightly (2013-12-02) on Win8 64-bit, and I can still reproduce the issue.

I just simply load the page, then click randomly on the page, so that the navbar and tab bar dissappear, and I wait for 4-5 seconds. Eventually, the scrollbar will dissappear.

Please see the attached screenshots for details.

Comment 13

[Jim Mathies [:jimm]]

(In reply to Manuela Muntean [:Manuela] [QA] from comment #12)
> Created attachment 8341070 [details]
> 2 screenshots.zip

I don't see a white band in "without scrollbar.png", although it's a screen shot of a page with a white background so.. hard to tell for sure. :) Can you try on a page with a colored background, for example - 

http://www.gutenberg.org/files/11/11-h/11-h.htm

Comment 14

[Manuela Muntean [Away]]

Attachment: other 2 screenshots.zip

- on Win 8 32-bit, with latest Nightly 2013-12-02

Please see the attached screenshots. Indeed, since the background of the webpage isn't white anymore, it is more visible that after the scrollbar dissappears, there isn't any white band to replace it.

I think this can be marked as verified now. Thanks!