When I click on "show 7 more" starred messages on the left side in chat, it only shows 4 and sometimes it shows only 2 messages. So maybe it depends on the length of the message. Could it be because it doesn't have a scroll bar? Or is it because I use Opera?
I had this problem without realising it until I had a chat with a couple of other mods and it boiled down to screen resolution.
If you don't have a scroll bar and your resolution is low you will just not be able to see the other messages. I had to plug my netbook into a proper monitor in order to get around this issue.