Normally, when a channel window is active, pressing the up and down arrow keys cycles through previously-entered text and commands. I'm running three different sessions, and on one of them, this works properly. However, on the other two, somehow this functionality has gotten turned off, and I can't figure out how, or how to turn it back on. Hints, pointers, suggestions?

Which version of Windows are you running?

What Firewall, Internet Security, Anti-Virus software(s) are you running?

Do you have any other hotkey software or media player software running?

Windows 7 Ultimate x64, Microsoft Security Essentials, and no other hotkey software or media players running. I'm not sure what the relevance of the questions is, given that in _one_ mIRC session, they still work - and it doesn't matter what order I start the sessions in; it's the same one that works. For that reason I suspect that it's something I did _in mIRC_, but I have no idea what, or where to look to compare settings/files.

The editbox history is always on, so it cannot be disabled. In the session where it does not work, are you using a multi-line editbox? If you are, the cursor keys are used to edit the line in the editbox. You would need to use the Control+Up/Down keys to scroll through the editbox history.

OK, now I feel stupid; that was exactly the difference between the sessions, and using Ctrl+... did in fact give me my history...

Thanks. You'd think after so many years of using mIRC, I'd have learned simple stuff like this...

I feel dumb for not thinking about that

I was going for the possibility of hotkey / keyboard hook interruption by a security software or media player.

Well... in this case, I think you can be excused, among other reasons because you were correctly assuming that I was using the current version - but what you didn't know, and which I failed to mention, was that I only recently "upgraded" from 6.21 ("upgraded", because it's actually a fresh install with partial recovered data, following a catastrophic disk failure), which didn't (as I recall) have the "automatic" setting for editboxes, which I've decided is the optimum setting.

With the "automatic" setting, I get IMO the best of both worlds, and I've now set all three sessions that way.