I personally recommend XN Resource editor, but anyway, you can find the info for the common event menu here:
CODE
RC DATA > TFORMEDCOMMONEVENT
if you look for:
CODE
object OverEdit1: TOverEdit
near the top, you'll eventually see :
CODE
MaxLength = 20
A few lines down, change that to however long you need.
I'm
not responsible for any problems this may cause however.