private void addActionButtonColumn(final int width) {

        final ActionCell<DataRetentionRule> actionCell = new stroom.cell.info.client.ActionCell<>(this::showActionMenu);

        final Column<DataRetentionRule, DataRetentionRule> expressionColumn =
                new Column<DataRetentionRule, DataRetentionRule>(actionCell) {

                    @Override
                    public DataRetentionRule getValue(final DataRetentionRule row) {
                        return row;
                    }

                    @Override
                    public void onBrowserEvent(final Context context,
                                               final Element elem,
                                               final DataRetentionRule rule,
                                               final NativeEvent event) {
                        super.onBrowserEvent(context, elem, rule, event);
//                        GWT.log("Rule " + rule.getRuleNumber() + " clicked, event " + event.getType());
                    }
                };
        dataGrid.addResizableColumn(expressionColumn, "", width);
    }
Add the columns to the table.
stroom-core-client/src/main/java/stroom/receive/rules/client/presenter/DataRetentionPolicyListPresenter.java