In the LIghtroom 4 Export menu, when exporting a video file, the extension in the File Naming Example doesn't get updated when the Video Format is changed. For photos, this happens immediately. For videos, it doesn't happen until the Export menu is closed (by clicking either Plug-in Manager, Cancel, or Export) and then re-opened.
Lightroom Version 4.0
Mac OS X Version 10.6.8