In the following case: <html> <head> <style> #p1 { -webkit-flow-into: named-flow; background-color: green; width: 50px; height: 50px; } .region { -webkit-flow-from: named-flow; height: 0px; } </style> </head> <body> <p id="p1"></p> <div class="region"></div> </body> </html> The content overflows the region and it should be visible (region-overflow is auto and this is the last region in the chain). In this case, WebKit should display a green rectangle, but it does not display anything.
There's a topic on www-style about 0 height regions: http://lists.w3.org/Archives/Public/www-style/2012Sep/0137.html The special case of the last region could contribute to that discussion.
The interesting thing here is that the content does not get displayed only if the region doesn't have a border/padding. As soon as the region has border or padding, the contents are correctly rendered.
This is probably another overflow related issue. Because the content is not a child of the region, it assumes there is nothing to paint so it skips the whole thing.
Created attachment 227256 [details] Patch
Comment on attachment 227256 [details] Patch r=me
Comment on attachment 227256 [details] Patch Clearing flags on attachment: 227256 Committed r165951: <http://trac.webkit.org/changeset/165951>
All reviewed patches have been landed. Closing bug.