Trying to set up 4 buttons (A, B, C, D) to filter data (based
on letter clicked) from XML to populate a List component.
When the letter is clicked, the variable used for the filter
must be changed accordingly. The filtered data should populate the
list box. However, clearly I'm missing a few nuts and bolts. I'm
trying to figure out how to drive the filter correctly via the
Click event and filter correctly.