Alfred Kayser Reporter
	Description • 16 years ago

Painting of background image sometimes fails in Nautipolis theme.

How to reproduce:
1. Install Nautipolis theme (1.8.43 is the latest)
2. Open a long webpage, so that there is a vertical scrollbar.
3. Place another window on top of FF
4. Slowly move the window downwards so that a piece of 'thumb' of the scrollbar becomes visible.
5. Notice how the background is painted differently than the rest of the thumb.
6. Forcing a complete redraw, the thumb is then drawn correctly.

This is not happening in FF3.0 (and older), and only started to happen in FF3.1 nightlies, since early november.

This is probably caused by bug 458487.

Note, the same symptom is also visible in the 'panel' buttons of the Tools/Addon window (using the Nautipolis theme).

	Alfred Kayser Reporter
	Comment 1 • 16 years ago

Note, this problem with the scrollbar can also be reproduced by making the window smaller or larger so that the ratio or size of the thumb changes.

	Robert O'Callahan (:roc) (email my personal email if necessary) Assignee
	Comment 3 • 16 years ago

Need a reduced testcase

	Alfred Kayser Reporter
	Comment 4 • 16 years ago

Reduced testcase:
Add the following in userChrome.css, use default theme, restart FF, open Tools/Options, and notice the background issue on the panel buttons when hovered upon...

@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);
@namespace html url(http://www.w3.org/1999/xhtml);
.paneSelector>radio{
	border:0px outset threedface!important;
	background:threedface url(file:///c:/mozthemes/NautiPolis/Common/global/toolbar-bg.png)!important}
.paneSelector>radio:hover{
	border:1px outset threedface!important;
	background:#CCCCFF url(file:///c:/mozthemes/NautiPolis/Common/global/toolbar-bg.png)!important}

	Alfred Kayser Reporter
	Comment 5 • 16 years ago

Note, this only seems to happen with an background image with alpha transparency, and a border set, and within 'XUL' space (or userChrome).

	Alfred Kayser Reporter
	Comment 7 • 16 years ago

This testcase show how the problem can be easily reproduced in content space, so it will impact webpages. 
The aspects that are needed to trigger this effect:
1. Semi-transparent background
2. Non-zero border width

What seems to happen is that whole background is drawn, but the background image has a vertical offset...

	Alfred Kayser Reporter
	Comment 9 • 16 years ago

Requesting blocking 1.9.1 as this is a layout/graphical/image regression (caused by bug 458487) from FF3.0 that we don't to appear in 3.1.

	Alfred Kayser Reporter
	Comment 10 • 16 years ago

Note, that with the last testcase, one can also show how partial redraws fails.
Move another window on top of the testcase and slowly drag it away so that the boxes are partially redrawn. It seems that the vertical offset is sometimes wrong and sometimes correct, depending whether the full height or only a part of the height of a box needs to be redrawn.

	Robert O'Callahan (:roc) (email my personal email if necessary) Assignee
	Comment 11 • 16 years ago

Seems to be fixed by the patch in bug 466258.

	Robert O'Callahan (:roc) (email my personal email if necessary) Assignee
	Comment 12 • 16 years ago

Should have been fixed on trunk by the fixing of bug 466258.

	Alfred Kayser Reporter
	Comment 13 • 16 years ago

Note, bug 466258 is blocking 1.9.1.

	Alfred Kayser Reporter
	Comment 14 • 16 years ago

Confirmed in Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2a1pre) Gecko/20081208 Minefield/3.2a1pre ID:20081208040950.
Can this also be pushed to 1.9.1?

	Robert O'Callahan (:roc) (email my personal email if necessary) Assignee
	Comment 15 • 16 years ago

Yes, it will be.

	Alfred Kayser Reporter
	Comment 16 • 16 years ago

Verified with Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b3pre) Gecko/20081213 Shiretoko/3.1b3pre ID:20081213034757.

Thanks!