Has this resolved since your post?
If not, try exiting WoW, reboot your machine (for good measure), then go back into WoW and see if the problem persists.
If it still does, try a complete UI reset. It’s quick, simple and easily reversible if it doesn’t fix any issues:
If that still doesn’t fix anything, you might dive into the suggestions given by the blue poster Kershew in the following tech support thread:
(Note: Be very careful on step #2. Kershew means for you to delete your “Battle.net” folder. NOT your “Program Files (x86)” folder. It’s just a bit unclear on that point, and I wanted to make sure no one’s nuking any Program Files folders. 
)
Good luck!