ColumnModel cm = new ColumnModel( cols );
store = new GroupingStore();
store.setReader( reader );
store.setDataProxy( proxy );
store.setSortInfo( new SortState( "num",
SortDir.ASC ) ); //NON-NLS
if ( this.dt.groupField != null ) {
store.setGroupField( dt.groupField );
}
cm.addListener(new ColumnModelListenerAdapter(){