columnVisible[i] = columns[i].isShownByDefault();
String displayValue = columnVisible[i] ? "table-cell" : "none";
DOM.setStyleAttribute((Element) headerCell.cast(), "display", displayValue);
CompoundValueSetter<Boolean> columnVisibleSetter = new CompoundValueSetter<Boolean>();
columnVisibleSetter.addSetter(new ElementVisibilitySetter((Element) headerCell.cast()));
columnVisibleSetters[i] = columnVisibleSetter;
columnVisibleSetters[i].addSetter(new ValueSetter<Boolean>() {
public void set(Boolean visible) {
repositionDragHandlers();
}