If it IS a Windows thing, then no... mIRC doesn't know the status of the window if Windows doesn't mark it active when it's "Not Responding." I don't know if it's a Windows issue or not, but it definitely sounds right to me. Any time you hang a program, there is a chance of things being done differently while it is hanging. It may be better to find a way around a loop that hangs mIRC. There are usually options to avoid that, depending on what you're doing.
Whether or not this is something that mIRC can "fix," I'm not sure. How will mIRC know the difference if Windows says it's not active while hanging or if Windows says it's not active because you have another window open on top? In one case, you want to mark the events and in the other case, you don't. I'm not sure that you can have both.
