final ComboBoxCellEditor editor = new ComboBoxCellEditor(dataProvider) {
			@Override
			protected void addNatComboListener(final org.eclipse.nebula.widgets.nattable.widget.NatCombo combo) {
				super.addNatComboListener(combo);
				combo.addKeyListener(new KeyAdapter() {

					@Override
					public void keyPressed(KeyEvent event) {
						if (event.keyCode == SWT.DEL || event.keyCode == SWT.BS) {
							combo.setSelection(new String[] { "" });
						}
					}

				});
			}
		};