if I start a new topic I can see blinking cursor in "Subject" position...
Moreover if you change "focus" to main message (leaving it empty) you will see that it become bolded in a black borderd box (as visual warning).
Again, if I try posting a message without Subject system will not let me go on but without losing every writen word (I'm actually using Mozilla Firefox).
Please let me know if you are going to give it some other try.
Keep me updated on it.