After thinking this through for a moment, I think the point here is that there are two fundamentally different ways of thinking about sorting. To the original p

After thinking this through for a moment, I think the point here is that there are two fundamentally different ways of thinking about sorting. To the original poster, it's a way of viewing the data. It doesn't change the original ordering of observations in the table, and it makes sense then to be able to turn it off... To the second comment, it is a way of actually changing the representation of the data. That's why you would expect it to be stable and dependent on the order that the sorting was done. Personally, I like the idea of it being a way of viewing the data rather than a change to the data. It would even make sense to be able to sort by column A, and then click to sort column B to breaks ties, and column C to further break ties ect. (though there would need to be a visual describing the precedence of the sorts to the user). Then, you can undone any of these by clicking a column twice more.