I fixed a weird CSS bug last week which I think is an interesting illustration of the difficulties of implementing a standard. One of the ways that I layout our website is by using CSS Tables to provide right-sidebars and content splits. One of our components consists of an image in a left-column, content and then a button bar in a right-column.
The whole strip of content was marked as display: table-row and the columns were display: table-cell.
On Firefox this was fine and the full width of the page was used with the correct proportions for the content blocks. On Chrome however the width of the whole component was around 75% of the whole page width (with the correct proportions). After a lot of examination it appeared that Chrome genuinely felt the page was narrower at that point.
It took a few weeks to get the necessary mindshift to fix it. The problem was the interpretation of how display: table-* works when you don’t have the full hierarchy. My interpretation is that the browser fills in the implied parent elements and that worked correctly in Firefox. In Chrome however I needed to change my table-row to table for the full width of the page to be used. The implied table wasn’t the full width of the page, while the explicit one was with the implied table-row occupying the correct full width.
This worked fine on Firefox as well so the problem was solved! Always have a top-element that defines display: table.