I did not know the name was so important. I'm not using groupers in the custom UI I'm building. Switching the name from Title to WC_Title did fix the problem.
Thanks Deathbane
Follow up question, since I'm learning as I work. What makes the name WC_Title so special? Is it defined somewhere else that I haven't found? Or how about WC_Frame or WC_Background? Is this something I'm going to have to re-examine with my other windows as well?
Thanks in advance.