Originally Posted by jpcavri
But I'm a bit lost:
1/If I click one one column, this one is selected and when I click to an other one, the fist is unselected and the second becomes the selected one.
When you click first one column header, and then a second, the sort order of the first is preserved within the second. So if you want to sort by author, and then sort by title within author, click first
the "Title" column header, and then
the "Author" column header. ie, you work from the "inside out".