Actually this doesn't seem true. The code has ", 20" in it (",20" in v10), which is a maximum number of messages to show.

This should be a config option too.

I think the backlog-time is actually completely ignored. We need to decide whether to just remove that, or implement both options. I verge on just having the static number, as it is safer performance-wise, and I don't think limiting by date is actually that useful (so what if old stuff shows? the maximum quantity is what matters).

so what if old stuff shows? the maximum quantity is what matters

I agree strongly with this. Even if you set it to say, one day, if say a chat room exploded with activity within the last 24 hours, that'll be a big performance hit as the chat loads all those messages.

This issue is rather confused, reflecting the confusion in the code.

It is now as you want. There's a "Chat messages to show" option, and it's not time based.