public void updateColumnHeadings() {
int cols = grid.getColumnModel().getColumnCount();
for( int i = 0 ; i < cols ; i++ ) {
ColumnConfig config = grid.getColumnModel().getColumn(i);
if( !config.isHidden() ) {
ColumnHeader header = grid.getView().getHeader();
if( header != null ) {
Head h = header.getHead(i);
if( h != null && h.isRendered() ) {
Filter f = getFilter(config.getDataIndex());
if( f != null ) {
h.el().setStyleName(filterStyle, f.isActive());
}