256996 - vertical text overlap in table from WebExpress

Status: RESOLVED INVALID

(Core :: Layout: Block and Inline, defect)

Description

[Robert Praetorius]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7) Gecko/20040803 Firefox/0.9.3
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7) Gecko/20040803 Firefox/0.9.3

This page (which seems to have been generated by MicroVision WebExpress) has
problems with text vertically overlapping text and other table elements.  The
problems are most pronounced near the bottom of the page (specifically in the
chart labeled Natural Rubber Latex).  The overlap (in proportion to text height,
anyway) increases with smaller font sizes.

Also seen with
Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.8a3) Gecko/20040817
Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.4) Gecko/20030624
Netscape/7.1 (ax)

The HTML here is probably not great (perhaps this is an evangelism issue?).
http://validator.w3.org/check?uri=http%3A%2F%2Fwww.pechsiam.com%2Fallabout4.htm
produces quite a bit of output.  However, IE 6 does a more legible job,
rendering it at various font sizes without overlap (not a perfect job though -
the text Specifications: (at the top of the 1st column in the Natural Rubber
Latex) is pretty much thrown away, although you can see the bottom of it
peeking out at the largest font size).

I'm not into the details of HTML tables (yeah, I know they're not just details
if you're implementing them or trying to exploit them to the fullest).  I did a
search for a matching bug and nothing jumped out at me.  But I wouldn't be
surprised if someone who knew the territory better found that this was a
duplicate of something already filed.


Reproducible: Always
Steps to Reproduce:
1. go to http://www.pechsiam.com/allabout4.htm
2. shrink the font size a few times (CTRL/-)
3. go to the bottom of the page

Actual Results:  
saw a bunch of text vertically overlapping other text and other table elements


Expected Results:  
rendered text without overlap

Comment 1

[Robert Praetorius]

Attachment: the page as rendered by Firefox 0.9.3

Comment 2

[Robert Praetorius]

Attachment: the page as rendered by IE 6

Comment 3

[Bernd]

We would need a reduced testcase here (www.mozilla.org/newlayout/bugathon.html)

Comment 4

[Erik Fabert]

Attachment: testcase

In this testcase I concentrated on the four links near the end of the page. As
you see, this problem is not related to tables, it is caused by the paragraphs
having a top margin of -14pt. In Opera and IE, this seems to be equivalent with
the default margin between paragraphs; Mozilla uses 1em as the default bottom
margin, so the margin gets smaller with smaller font sizes.

Comment 5

[Bernd]

I believe the margins collapse

Comment 6

[Gérard Talbot]

After carefully examining attachment 160641 [details] and carefully reading the bug report description, I am convinced that the observed vertically overlapping text over other text and over other table elements is due to margin collapsing. IE6 was notoriously known for having lots of bugs with margin collapsing. Therefore, I am

Resolving as INVALID