How to coloring lookup metod

public client static void lookupItem(FormStringControl _ctrl)
{
    SysTableLookup          sysTableLookup = SysTableLookup::newParameters(tableNum(InventTable),_ctrl);
    Query                   query = new Query();
    QueryBuildDataSource    queryBuildDataSource = query.addDataSource(tableNum(InventTable));

    sysTableLookup.addLookupfield(fieldNum(InventTable,ItemId));
    sysTableLookup.addLookupMethod(tableMethodStr(InventTable,defaultProductName));
    sysTableLookup.addLookupMethod(tableMethodStr(InventTable,itemGroupId));
    sysTableLookup.addLookupfield(fieldNum(InventTable,NameAlias));
    sysTableLookup.addLookupfield(fieldNum(InventTable,ItemType));
    sysTableLookup.addSelectionField(fieldNum(InventTable,Product));

    sysTableLookup.parmQuery(query);
    sysTableLookup.performFormLookup();
}