271364 - display of certain block elements in nested floated boxes changes when resizing the window

Status: RESOLVED FIXED

(Core :: Layout: Floats, defect)

Description

[Sebastian Winkler]

User-Agent:       Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.8a5) Gecko/20041122 Camino/0.8+
Build Identifier: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.8a5) Gecko/20041122 Camino/0.8+

Well, this is kind of difficult to describe, so I'll attach a test-case.
It's like this: a margin:auto or text-align rule applied to a block element
which resides inside the second of two nested floated boxes, which do not have a
width defined, but of which the first contains another not-floated block
element, are honored until the window is being resized. Then the display changes.

I was originally out to demonstrate the opposite effect (at first the style is
not honored, after resizing the window it is) which was the case that actually
occurred to me while developing a complex form layout, but when I tried to
reproduce it for the test-case, this is how it turned out. The underlying bug
though, as I reckon, must be the same.

I am not even sure whether or not the styles should be honored, though I fear
that they shouldn't as the containing floated boxes have no width defined.
Anyway I am sure that the way they're handled should not change when the window
is resized!

This strange behavior appeared only recently: in my Nightly Latest Camino build
from 2004-10-15 the rules where still being fully honored.

Reproducible: Always
Steps to Reproduce:
1. download my test-case or recreate the conditions described above
2. load it into a Mozilla browser
3. resize the browser window

Actual Results:  
the margin:auto / text-align rule is no longer being honored.

Expected Results:  
honoring of styles should be independent from use interaction like resizing the
browser window

Comment 1

[Sebastian Winkler]

Attachment: initial test-case

Comment 2

[dolphinling]

I'm having weird stuff happen as I try to testcase this further. If a certain
element (the h3 in the original testcase) isn't there, it displays properly. If
it's there as a (nonfloating) div, it displays improperly all the time. If it's
there as an h3, it displays improperly at first, but properly on a resize. In
any case these testcases are also slightly more reduced.

Comment 3

[dolphinling]

Attachment: testcase with no extra element

Comment 4

[dolphinling]

Attachment: testcase with an unfloated div

Comment 5

[dolphinling]

Attachment: testcase with an h3

This one's even stranger--if you remove the margin from the h3, it displays
just like the unfloated div. This testcase just shows the normal h3, though.

Comment 6

[Andrew Schultz]

floats

Comment 7

[Martijn Wargers (dead)]

I can see the bug in a 2006-12-07 trunk build, but not anymore in the 2006-12-08 trunk build, so fixed by the reflow branch landing.