this is something for the admins: when clicking "Edit" on the "Preview Question" screen, the title field gets cleared. A little bit annoying… :-)
I guess this is a bug worth fixing…
Having just gone through the process of creating a question, previewing it and editing, and previewing again, I can tell you that it works as expected on my system. See this demonstration.
All I can think of is that you clear your cache, and maybe ensure that cookies are enabled (although I am not certain this would cause the behaviour you are seeing)