Again, thank you for the reply. You have an interesting idea. The only problem with what you are suggesting is that it will not work the way I want for the 'extended' mode of selection. In other words, try to select a number and a letter at the same time (hold CTRL down to do that) and you will see that the selectbackground for the entire tree is adjusted based on the bottom-most selected item. Expressed a different way, select 1.A and 2 and both selectbackgrounds will be white, or select 1 and 1.B and both selectbackgrounds will be blue. I am starting to get the impression that what I am trying to is impossible in Tk::HList ...