Thanks, SD. That's exactly what I was expecting to happen.
The main PC (XP Pro SP2) has "remember ... settings" turned on, and the folders stay as I want them. The desktop folders open "sized" and with icons. The file list ones open in detailed list view. It doesn't matter what order I open them in, they always do the same.
The laptop (XP Pro SP2) didn't do that. Now I have set the switch the other way, it seems to. Can a software switch be wired the wrong way round?
Mind you, the laptop is doing a few other strange things, too. Skype always opens with a splash screen, and maximised despite the "trigger" saying /nosplash /minimized. Perhaps I should exorcise it