I set the style to 'Midnight' and I am now unable to change to other styles. This may be an issue with vBulletin, but I would still like to know how to correct this. When I click the style chooser at the bottom of the page all I get is the placeholder text 'Quick Style Chooser'.
EDIT: I still had some other tabs that still had the default theme selected, so I tried all the other themes to see if this issue occurred; it is only an issue with the 'Midnight' theme. While I have corrected it for myself, this issue still should be corrected.