[Closed] ListBoxSample Questions

I want to add something similar to the ListBoxSample's list box used for Undo but want the user to be able to select just one single entry, not have the behaviour I see where multiple entries are automatically selected starting from the first entry in the list.

I have tried setting the listbox style SetMultiplSel off but this doesn't change things.

So - aim is - have a listbox where the user selects any one entry in the list.