308222 - overflow:auto on div after adjusting margin-left problem

Status: RESOLVED FIXED

(Core :: Web Painting, defect)

Description

[Magnus Melin [:mkmelin]]

In the testcase I'm about to attach, a wide div containing other divs are
scrolled  so that only one of the innner divs are visible at the time. 

When the innner div has overflow:auto - and the div is scrolled back - parts of
the div next to it is left visible. Also, the right margin of the inner div does
not display until you drag the mouse over it. So basically, things are left
partly  visible outside the margin of the div. 

This works fine in firefox 1.0.x, opera8, ie. Problems in recent nightlies, and
at least back to 2005-03-01, I didn't have any older build to test with. Both
win and linux.

Comment 1

[Magnus Melin [:mkmelin]]

Attachment: testcase

Click the button in this testcase twice. Notice stuff are kind of left behind.

Comment 2

[zug_treno]

Reproducible with Mozilla 1.8a5 but WFM with Mozilla 1.8a4.

Comment 3

[Magnus Melin [:mkmelin]]

About the testcase: When switching to another tab or minimizing the window
you'll notice that the garbage goes away. 

Comment 4

[Robert O'Callahan (:roc) (email my personal email if necessary)]

It would be helpful if you could reduce this testcase to the bare minimum
required to show the bug.

Comment 5

[Martijn Wargers (dead)]

Attachment: testcase2

This is a minimal testcase that shows the bug.

Comment 6

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Attachment: fix

This fixes the bug, but I'm a bit concerned about the potential impact. I don't
immediately see a better way though.

Comment 7

[Robert O'Callahan (:roc) (email my personal email if necessary)]

In particular I'm concerned that hiding and showing child windows might be slow
or have some other impact (e.g., affect focus).

Comment 8

[Magnus Melin [:mkmelin]]

Any chance this fix will get checked in? Slow would be better than all wrong...
if it's not extremely slow.

In the testcase: the garbage isn't left behind with overflow:visible either btw.
overflow:auto and overflow:scroll get's it wrong.

Comment 9

[Robert O'Callahan (:roc) (email my personal email if necessary)]

This is probably too risky for branch at this point. For trunk this problem will
go away with some other work.

Comment 10

[Robert O'Callahan (:roc) (email my personal email if necessary)]

On trunk there's some flickery stuff on Windows but it's very transitory, you always end up with the right rendering. I hope that will go away with Compositor. We certainly aren't going to fix this on the 1.8 branch. Since this is labelled a branch bug, I probably should call it WONTFIX, but it makes more sense to point this at trunk and mark it FIXED.