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Re: [CSS21] Why do overflow values other than 'visible' establish a new block formatting context?

From: L. David Baron <dbaron@dbaron.org>
Date: Sun, 1 Apr 2012 20:35:08 -0700
To: Daniel Tan/BoltClock <lists@NOVALISTIC.com>
Cc: "www-style@w3.org" <www-style@w3.org>
Message-ID: <20120402033508.GA6895@crum.dbaron.org>
On Monday 2012-04-02 11:24 +0800, Daniel Tan/BoltClock wrote:
> This leads us to wonder: why is this so? I am under the impression
> that removing floats from normal flow will interfere with clipping
> and scrolling, but am not sure how exactly. I can't seem to find any
> previous threads in the mailing list that discuss the overflow
> property in particular.

Fundamentally, because if the spec didn't say this, then having
floats intersect with something that's scrollable would require the
browser to rewrap (around intruding floats) the contents of the
scrollable element every time it scrolls.  This is technically what
CSS 2.0 required, but it was never implemented, and it would have
been a huge problem for speed of scrolling.

-David

-- 
𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                           http://www.mozilla.org/   𝄂
Received on Monday, 2 April 2012 03:35:36 GMT

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