@Thrull: If you read that thread a bit more, you'll see reasons why your examples aren't going to work well. You already edited to point out why total lines isn't going to work. You also can't check the last lines because it's very possible to have two lines (or more) be the same. There are some examples of how to get accuracy up to around 99.9% or so (checking top, bottom, and at least one middle line... more increases accuracy) and for most things, that really is enough.
@FroggieDaFrog: It doesn't take that much code to check multiple lines for changes and it's very accurate. The chances of it not being correct are extremely low. You can even avoid such a line check and just save the buffer and check it's hash. Of course, that's more CPU intensive and depending how often your check it, it may not be worth it. But it requires very little code to do.
In any case, this should be very easy to add and would be worth adding. mIRC already knows when there are changes, so providing an event for them shouldn't be hard. It probably needs to be limited in scope, though... as mentioned, you don't want it to override on text or anything else.
