ERM... alt+F4 closes the active window, not the tab, irc included... and that doesn't come from IRC, thats a windows thing.
alt+f4 closes the active window but ctrl+f4 closes the active tab
Go try mIRC .... open a channel then open a private convo with someone. Try ctrl+f4 .... it will close the private convo. Itll close the channel window too if you try
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