Bug 19123 – An element with block formatting context adjacent to a floated block has phantom right margin.

• Component: Layout and Rendering
• Status: RESOLVED DUPLICATE

[Philippe Wittenbergh]

An element that establishes a new block formatting context – overflow:hidden in testcase – (per CSS2.1:9.4.1), has a left-margin, and is adjacent to a left floated block, has a phantom margin on the right side, equivalent in width to its left-margin.

Actual result: a 20px gap at the right of the element.

Expected result: no gap. Compare rendering in (recent) Gecko 1.9 builds.

tested with WebKit-SVN-r33561, Safari 3.1.1 and anything older

Note: with a right floated element and a right-margin on the element with block formatting, the margin is applied between the float and element, contradicting CSS2.1:9.5

[Philippe Wittenbergh]

Created attachment 21225 [details]
testcase

[Philippe Wittenbergh]

Created attachment 21227 [details]
testcase2

for completeness' sake, a testcase with float:right and margin right on the main block. The margin-box should slide under the floated block (per CSS2.1:9.5)

I think this is a duplicate.

[Oded Arbel]

I think this is the same issue I have - a floated element causes the elements it floats next to, if they have both margin and   overflow set to non-visible, to have a phantom right margin: http://geek.co.il/articles/webkit-margin-with-float-bug.html

As the testcase in this URL shows, the phantom margin is sized according to the size of the floated element.

I can reproduce this with all webkit installations (Safari/Win, Safari/MacOSX, Chrome/Win, Chromium/Linux and even Konqueror), including nightlies. Bug #22089 may also be related.

[Paranoid Android]

Same as bug 22089 (which has a somewhat clearer test case).

[Jonas Munk]

Created attachment 44977 [details]
Test case showing float-overflow-margin bug

Thought i might as well attach this test case since I already made it, hope it helps :-)

This technique is very common so I would consider it to be fairly critical.

[Darth]

Similar downstream bug http://code.google.com/p/chromium/issues/detail?id=69052

[Dave Hyatt]

*** This bug has been marked as a duplicate of bug 79046 ***