Bug 40113 – Strange layout bug involving floats and overflow:hidden

• Component: CSS
• Status: RESOLVED DUPLICATE

[Lea Verou]

Created attachment 57754 [details]
Reduction that illustrates the bug

See attached testcase.
#content should not have the gap on the right, and it doesn't in ALL rendering engines (Trident, Presto, Gecko) but Webkit-based ones.

If you remove overflow:hidden the bug disappears. If you remove #sidebar, it disappears again. I have no idea what might be causing it.

[kyounga]

It looks the problem between left-float and left-margin. 

I guess that the "content" width is caclulated as [the containg block's available width of "content"(960-siderbar's width) - left-margin(18em) value]
But, margin is the distance from containing block not neighbor block. 
So, left-margin calculated from left edge of containing block("wrapper")

BTW, in case of overflow:hidden, I have two theory. 
1. The line box of "content" has right value and draw the bgcolor.
   But, the line box has no background-color. 
   The painting in webkit draws the inherited background-color from parent? not transparent? 

2. Or the block width calculation is wrong only when it has "overflow:hidden"
   But, "overflow" property should effect on "drawing" not "rendering", isn't it? 

I'll analize this bug with latest nightly build.

*** This bug has been marked as a duplicate of bug 35910 ***