@@ -140,6 +140,36 @@ Scrollable overflow</h3>
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set of things extending outside of that box's padding edge
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for which a scrolling mechanism needs to be provided.
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+ The <dfn>scrollable overflow region</dfn> is the non-rectangular region
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+ occupied by the <a>scrollable overflow</a> , and the
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+ <dfn>scrollable overflow rectangle</dfn> is
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+ the minimal rectangle whose axis is aligned to the box's axes
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+ and contains the <a>scrollable overflow region</a> .
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+
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+ The <a>scrollable overflow region</a> of a box includes:
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+ <ul>
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+ <li> the box’s own content and padding areas
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+ <li> all line boxes directly contained by the box
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+ <li> the margin boxes of all in-flow and floated boxes
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+ for which it is the containing block
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+ (accounting for transforms as described below).
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+ <li> the padding boxes of all absolutely-positioned boxes
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+ for which it is the containing block
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+ (accounting for transforms as described below).
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+
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+ Issue: Blink (and presumably WebKit) use the margin box here. Is that better?
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+ <!-- testcase: http://software.hixie.ch/utilities/js/live-dom-viewer/?%3C!DOCTYPE%20html%3E%0A%3Cstyle%3E%0A%20%20div%20%7B%20height%3A%2050px%3B%20overflow%3A%20scroll%3B%20border%3A%20solid%3B%20position%3A%20relative%3B%7D%0A%20%20p%20%7B%20margin%3A%2025px%3B%20background%3A%20red%3B%20%7D%0A%20%20q%20%7B%20position%3A%20absolute%3B%20background%3A%20blue%3B%20top%3A%2025px%3B%20margin%3A%2025px%3B%20%7D%0A%3C%2Fstyle%3E%0A%3Cdiv%3E%0A%20%20%3Cp%3ETest%20%3Cq%3ETest2%0A%3C%2Fdiv%3E -->
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+
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+ <li> the <a>scrollable overflow regions</a> of all of the above boxes
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+ (accounting for transforms as described below),
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+ provided they themselves have ''overflow: visible''
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+ (i.e. do not themselves trap the overflow)
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+ and that overflow is not already clipped
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+ by the 'clip' or 'clip-path' properties.
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+
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+ Issue: What about masking?
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+ </ul>
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+
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<p class="issue">
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The following definition should be rewritten to use
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the concept of <a href="http://dev.w3.org/csswg/css-transforms/#3d-rendering-context">3D rendering context</a> [[!CSS3-TRANSFORMS]]
@@ -201,13 +231,8 @@ Scrollable overflow</h3>
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the elements should probably count
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only towards the overflow of the element that flattens them.
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- The <dfn>scrollable overflow region</dfn> is the non-rectangular region
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- occupied by the <a>scrollable overflow</a> , and the
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- <dfn>scrollable overflow rectangle</dfn> is
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- the minimal rectangle whose axis is aligned to the box's axes
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- and contains the <a>scrollable overflow region</a> .
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- Note that the <a>scrollable overflow rectangle</a> is a rectangle
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- in the box's coordinate system, but might be non-rectangular
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+ Note that the <a>scrollable overflow rectangle</a> is a always rectangle
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+ in the box's own coordinate system, but might be non-rectangular
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in other coordinate systems due to transforms [[CSS3-TRANSFORMS]] .
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<h3 id="border-box">
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