http://www.fujirumors.com/behind-x-e2-firmware-2-00/ "What Fuji doesn’t (at least officially) say is that they have also fixed a bug that caused Pre-AF and AF-C to secretly focus with the upper-left AF frame when the user changed the size of the actually selected AF frame to a non-default size. This could explain why some users reported that their X-E2 didn’t properly track subjects in AF-C mode: They might have selected a non-default AF frame size."