As per my knowledge you are one of those people who suffer from backlight ptoblem. So my guess is that may be alpha 7 caused some problem with touch sensitive buttons (even dhiru has mentioned it in bug list). In my case same thing was happened with me related to brightness bug. Even if I flash xxkpe brightness bug was appearing on it also. That was really wiered...!!
So try in this way...flash xxkpe with .pit file. Then flash ddlf2. Then cm10.1 alpha 6 (its one of the good stable rom without touchscreen bug). Then remove battery for 5 min. And finally start phone. And check same bug appears or not. If everything goes well then flash alpha 8 (its the best stable rom)
i used to have the brightness bug on cm 7.and early builds of cm10.1 but not after alpha 4 i guess.i flashed ddlf2 directly over alpha 7.but it doesn't work.
but why do i need to flash xxkpe since we can flsh lf2 with the pit file.anyways i'll try if you say so.
EDIT: i was on alpha 6 and not alpha 7.
---------- Post added at 01:16 AM ---------- Previous post was at 01:05 AM ----------
so this is what happened.
a month on alpha 6 and then touchscreen stopped responding.
flashed ddlf2 over it problem was still there.in addition the light sensitive buttons stopped working.
then i thought of rooting the phone to flash alpha 8 and see if the problem is still there.
rooted the phone using the ddlf2 cf root kernel.
phone's touchscreen and light sensitive buttons started working for 10 minutes went dead again :|
lets see what happens after flashing alpha 8
EDIT:no luck with alpha 8 too.