Fix row select issue with  select.row.selectById() when multiple = false

I've found, clearMark isn't working properly. With this dirty fix one can use the single select feature or select/row. This fixes issues with select.row.selectById().
When I set select.row.multiple to false, single selection with mouse (on row header) works fine. But when I issue  select.row.selectById() then the original selection remains visible, plus the new one is selected.