I am i ride leader and use ZML on my Apple iPhone to give instructions. The longer the ride and the more messages it becomes un responsive. For example the 24 hour ride It was unusable to message people. The more chat or history the slower it gets. Its like the ZML consumes all the memory.
Even if I exit the app and properly close and reopen it is still slow. Why do you need to keep the whole of the chat and not the last 20 messages?