At least one of these default pane view check boxes must be selected.
In the Query and View Designer pane of the Options dialog box, at least one of the required Default pane view check boxes is not selected. You can select any or all of the available panes to display by default in the Query and View Designer: Diagram, Grid, SQL, Results.
Other ResourcesQuery and View Designer Tools (Visual Database Tools)
Options (Designers/Table and Database Designers Page)