Some lines are being missed from the log
Some lines that are appearing in your chat box, in front of you, won't be presented in your history/log.
Steps to reproduce
Tested with IRC channels.
Join to an MUC channel (IRC channel, in this case) and ask users to send messages to the chat rapidly, you'll notice that some of the messages are not included in the history log of that channel.
OS version: Salix OS 13.1.2 (Slackware 13.1.0 based)
GTK version: 2.18.9
PyGTK version: 2.16.0