list box - 1st item alone OR mult items (not including the 1st)
If user selects 1st item in list box, I want to deselect all others. But, if the user selects the 2nd, 3rd, or 4th item I want to deselect 1st item only.
In other words, valid choices are:
1) 1st item only ("all")
2) one or...