715461 - Firefox shows two <div>-blocks one below the other instead of side by side

Status: RESOLVED WORKSFORME

(Core :: Graphics, defect)

Description

[user979]

Attachment: Screenshot of erroneous behaviour of Firefox and of correct behaviour of Chrome, Opera and IE9

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0.1) Gecko/20100101 Firefox/9.0.1
Build ID: 20111220165912

Steps to reproduce:

Call the website 
http://www.alternate.de/html/product/listing.html?navId=11600&tk=7&lk=1863
or choose any other product in the HARDWARE product-area of this well known german computer shop.


Actual results:

Firefox shows two <div>-blocks one below the other instead of side by side. In this case: The product list is shown below the navigation bar on the left instead of right of the bar.
This looks terrible and requires a lot of vertical scrolling. A good survey no more exists.


Expected results:

Firefox should show the two <div>-blocks side by side, so that the product list is shown on the right of the navigation bar.
See on the attached PDF containing two screenshot that show the erroneous behaviour of Firefox and how Google Chrome displays the website correctly, as well by the way, as IE9 and Opera.

Comment 1

[Alice0775 White]

This site layout is depend on font size or text zoom level.

Comment 2

[(mostly gone) XtC4UaLL [:xtc4uall]]

Indeed, if I zoom out one Step (1x CTRL+-) it's reproducible for me.

Doing the same against Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0.1) Gecko/20100101 Firefox/4.0.1 is WFM.

Comment 3

[(mostly gone) XtC4UaLL [:xtc4uall]]

Last good nightly: 2011-06-02
First bad nightly: 2011-06-03

Pushlog:
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=9a6c139a4e58&tochange=8fff6db8b016

Disabling HWA makes no Difference.

Comment 4

[user979]

I tried now - according to the comment of Alice0775 White  and XtC4UaLL with different text zoom levels with CTRL+- / CTRL++ from very small to very large.

In all the zoom steps I tried there were only two steps, where Firefox 9 displayed the page correctly: one very small zoom-level and one medium zoom-level.

Has the Alternate-webpage linked above a very bad or erroneous page-layout (HTML-design error) or is it really a Firefox bug?

Hints for a webpage design error are that I didn't notice this effect on other webpages yet.

Hints for a Firefox bug are, that the other cited web browsers display this page correctly in (nearly) all zoom-levels.

With one excpetion:
Chrome and IE9 show the same display-error when using their smallest zoom-level, which is very, very small. In all other zoom levels it's OK on Chrome and IE9, so in practical usage this has no importance on these browsers. 
On Opera however it's OK with every zoom-level.

So may be it's a combination of error-causes:
A bad page-layout or javascript code (design error) in combination with a unsufficient fault-tolerance of Firefox for this kind of errors.

Who can check the page layout / javascript code for errors?
If an error would be found there, one could systematically test or code-review firefox on how firefox handles such layout-/javascript errors.

Comment 5

[Alice0775 White]

Generally, web designer should not assume the width of the font for the purpose of the fixed layout of the web page.

Workaround 
Set gfx.font_rendering.cleartype_params.force_gdi_classic_max_size to 0 and restart.

Comment 6

[[Baboo]]

Please also note that in IE9 this page is rendered in IE8 mode per default, so you would've to press F12 and change the "Document Mode" there to IE9 to compare it to Firefox with the GDI-like font rendering fallback for small sizes disabled (workaround mentioned in previous comment).

Comment 7

[user979]

@Alice0775 White:

I tried the workaround by changing gfx.font_rendering.cleartype_params.force_gdi_classic_max_size to 0 (value before was 15) and restarting but it didn't change anything in behaviour: still exactly the same behaviour as before.

Comment 8

[(mostly gone) XtC4UaLL [:xtc4uall]]

FWIW, here the (expectedly) HG Bisect Result:

The first bad revision is:
changeset:   70482:077b3514036d
user:        Robert O'Callahan <[e-mail]>
date:        Fri Jun 03 16:31:08 2011 +1200
summary:     Bug 661471. Part 4: Force DirectWrite to use 'GDI Classic' rendering for sans-serif 'core Web fonts' of size < 16 pixels. r=jdaggett,jfkthame

Comment 9

[(mostly gone) XtC4UaLL [:xtc4uall]]

the rendering given site's menus is WFM in all standard zoom levels against
Mozilla/5.0 (Windows NT 10.0; WOW64; rv:44.0) Gecko/20100101 Firefox/44.0 ID:20160210153822 CSet: 60e96806ff1c9fb51f3df31ccd1db33f5f320e75 and
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:47.0) Gecko/20100101 Firefox/47.0 ID:20160219030248 CSet: 9166484e331b685c8b7027bedcf328421029ac59
=> resolving WFM