Not really hidden, it's very common (and extremely useful - Fitts's law FTW) user interface convention. I already became conditioned - I keep middle-clicking t

Not really hidden, it's very common (and extremely useful - Fitts's law FTW) user interface convention. I already became conditioned - I keep middle-clicking to close tabs automatically in every application, feeling something is broken when it doesn't work. Though Mac people don't usually have more than 1 button, so I kind of understand obsession about workarounds :).