Question

1. When the user clicks on a item in my single-select ListBox, the item is selected.
2. When the user clicks on a item the second time, the item is not unselected unless they are holding the control key.

What is the recommended way to change #2 to not require the control key?

Answer 1

Make sure the selection mode is Multiple. By selecting multiple:

you can use the mouse to select and deselect any item(s) you want with just a mouseclick. But if you want only 1 selected item at a time, you’ll have to deselect the other items in code in the SelectionChanged event.

Source

Private Sub MainList_SelectionChanged(ByVal sender As System.Object, ByVal e As System.Windows.Controls.SelectionChangedEventArgs)
    If e.AddedItems.Count > 0 Then
        Dim valid = e.AddedItems(0)
        For Each item In New ArrayList(MainList.SelectedItems)
            If item IsNot valid Then MainList.SelectedItems.Remove(item)
        Next
    End If
End Sub