458033 - Large rowspans stretch tables vertically

Status: UNCONFIRMED

(Core :: Layout: Tables, defect)

Description

[Matthew Wakeling]

User-Agent:       Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.0.1) Gecko/2008071420 Iceweasel/3.0.1 (Debian-3.0.1-1)
Build Identifier: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.0.1) Gecko/2008071420 Iceweasel/3.0.1 (Debian-3.0.1-1)

When rendering a table with style border-collapse: separate, cells seem to have a minimum height of the content plus some small amount per rowspan. This becomes a problem when trying to make two columns have slightly differing numbers of rows by using lowest common multiple rowspans, as shown in the first table in the example web page.

I know this is an obscure problem, but it may exhibit itself in undesirable behaviour in other situations. If you set border-collapse to collapse, then the problem goes away.

Reproducible: Always

Steps to Reproduce:
1. Create a table, and set the style border-collapse to separate (the default).
2. Have a row that has a large rowspan, and no other cells forcing the size of the row.
Actual Results:  
The table is very large vertically.

Expected Results:  
The table should be no larger than if the rowspan was one.

Comment 1

[Matthew Wakeling]

It seems that the amount of vertical space added to the rows is non-linear. Three data points are:

Rowspan = 1, row height = 21 pixels
Rowspan = 20, row height = 36 pixels
Rowspan = 50, row height = 96 pixels

Comment 2

[Bernd]

Attachment: testcase from url

Comment 3

[Bernd]

this depends both on the cellspacing and the cellpadding. Both of them default to 1px. Setting them explicitly makes the problem more obvious.