Aircraft N-Number Reservation
Currently, the default settings for Microsoft's Internet Explorer (IE) version 11 don't work properly with another Microsoft product that this site also uses.
You will need to click the Tools Menu (the little sprocket icon in the NW corner of your browser window) and add faa.gov to your "compatibility view" settings. Otherwise, this problem will persist until that issue is resolved.
Other browsers are available that function properly, for example: FireFox, Opera, Safari, or Chrome.