Shoutbox

The "Ctrl + close" feature works from the taskbar aswell. So if you right click the taskbar button of your tabbed conversation window, hold control, and press close, this will close all of tabs in your conversation window. If you have Simlar Taskbar Buttons Grouped (in XP) and have the Contact List Window button there too (and they are grouped), then you have to single left click that, and then right click the conversation window (but I imagine you already knew that).

However, if you right click the Grouped Similar Buttons, and hold Ctrl and click "Close Group" this will send the contact list to the systray, and will only close the front, conversation tab, just as it would without holding Ctrl. I don't imagine that there is much Patchou could do to change that behaviour. But I think the first solution presented here pretty much addresses your desire.