Twenty Fourteen display error

I’d mentioned this error with Twenty Fourteen previously, but just stumbled on the cause in case anyone else comes across it.

I’m not currently using Twenty Fourteen on any live sites, so it’s not a priority, but so that everyone is aware, I’ll mention that when using the standard WP Twenty Fourteen theme in conjunction with the uf2 plugin to provide ad hoc microformats2 support (WordPress should really be more forward thinking and support mf2 out of the box), the display of the site is thrown out of whack and it only displays the left column and compacts the main content area into ~300px rather than the full ~900px. For those familiar the 3×2 grid of featured posts on the front page displays as a single 1×6 column instead, (akin to making it look like its outputting for a mobile platform rather than desktop).

I’ve used (and done tests with) several dozen other themes (including most of the WordPress default yearly themes) in conjunction with the uf2 plugin and haven’t seen anything like this, which makes me confident that it’s a small bug with the Twenty Fourteen theme rather than the plugin.

Based on what uf2 does, my strong suspicion is that the additional microformat classes that are thrown into the Twenty Fourteen theme are conflicting with the base CSS. This means that 2014 is likely going overboard and not differentiating well between classes used strictly for theming and classes which are solely meant to be used for semantic markup.