Not sure why, but the previous conversation about this is locked. The problem did not resolve itself after a conversation in 1.0. Message windows still appear blank when they are opened, even if I was just chatting with the same user.
My preferences are set to Always remember the last 20 lines.
Yeah, we really need to grey out the history checkbox if logging is off. In 0.89.1 it would still work, but it was really misleading because we were actually logging the last N messages from each chat, which is... not exactly what people turning off logging for privacy reasons would be expecting.
Since the last update, I'm having the same issue - windows often open blank, or with the previous session missing (but sometimes one before that shows, oddly enough!) - and I have message logging turned on, and set to always display the last twenty lines.