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Re: c5504-mrgn-l-002 is invalid

From: Alan Gresley <alan@css-class.com>
Date: Wed, 01 Dec 2010 23:02:17 +1100
Message-ID: <4CF63949.4060308@css-class.com>
To: fantasai <fantasai.lists@inkedblade.net>
CC: "L. David Baron" <dbaron@dbaron.org>, public-css-testsuite@w3.org
On 1/12/2010 2:54 PM, fantasai wrote:
> On 10/14/2010 03:05 PM, L. David Baron wrote:
>> http://test.csswg.org/suites/css2.1/20101001/html4/c5504-mrgn-l-002.htm
>> http://test.csswg.org/suites/css2.1/20101001/xhtml1/c5504-mrgn-l-002.xht
>> assert that something that sticks out of a page to the left should
>> cause a horizontal scrollbar. This requirement is not defined by
>> the spec and is interoperably *not* implemented.
>>
>> The test should be removed.
>
>  From http://www.w3.org/TR/CSS21/visufx.html#overflow-clipping
> # Whenever overflow occurs, the 'overflow' property specifies
> # whether a box is clipped to its padding edge, and if so,
> # whether a scrolling mechanism is provided to access any
> # clipped out content. ^^^^^^^^^^^^^
> ^^^^^^^^^^^^^^^^^^^
>
>  From http://www.w3.org/TR/CSS21/visufx.html#overflow
> # The 'visible' value when used for the viewport must be
> # interpreted as 'auto'.
>
>  From the definition of 'overflow: auto':
> # The behavior of the 'auto' value is user agent-dependent,
> # but should cause a scrolling mechanism to be provided for
> # overflowing boxes.
>
> The test is marked as 'should', and is therefore not required
> to pass. But I don't see any reason to remove it as it does
> not in fact appear to be invalid.
>
> ~fantasai

I don't agree with this reason. The test case may not be invalid but 
what is the testing?

The negative margin on the <p> causes it to go into hidden overflow 
which begins at the margin edge of the <body>. A test done with RTL 
would produce a scrollbar. Changing part of and adding this CSS produces 
a scrollbar.

body { text-align:right; }
.five { margin-right: -10px; }


Authors often use a negative margin to hide particular elements / 
content within the hidden overflow. It's not a case that it should or 
should not be hidden, it's what has been implemented for years.


-- 
Alan http://css-class.com/

Armies Cannot Stop An Idea Whose Time Has Come. - Victor Hugo
Received on Wednesday, 1 December 2010 12:02:53 GMT

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