Last week I posted about a new application that exploited Facebook’s available space where they typically place a banner ad. As of today, the thin ice that Flyer Exchange was skating on has cracked. Facebook has announced that they are going to start blocking these applications. According to Facebook:

We’re planning on fixing a bug that some app developers are taking advantage of to display information in the Facebook chrome, outside the application canvas page.

This fix will be a breaking change for developers using absolute or fix positioned elements (to be specific, we will be adding a “position: relative” to the canvas page container) so we’re delaying the general fix in order to ensure everyone has time to update their applications. We’ll post more details when we close on a timeline.

The bottom line is that any Facebook application using absolute positioning CSS is not going to work perfectly anymore. If your application has absolute CSS then remove it! This exploit shows one of the downfalls of the platform. There is no guarantee that everything you can do on a website is going to work within Facebook without some sort of minor hacking.