I hope someone is working on this problem that seemed to start with iOS6: the send button should become active as soon as a character is typed into a reply, but most of the time it stays grayed out. Sometimes it does work, usually not, even after force quitting and relaunching IPF. It may not be random, but depend on which thread is open, not sure about that. In one case, I could not write a reply, yet I could edit one of my earlier replies in the thread.
milliHelen: amount of beauty required to launch one ship.