// --------------------------------------------------------------------
// STEP 4: set up a display and ui components to show the visualization
m_display = new Display(vis);
m_display.setItemSorter(new ItemSorter() {
public int score(VisualItem item) {
int score = super.score(item);
if ( item.isInGroup(group) )
score += item.getInt(TOTAL_RECEIPTS);
return score;