Displaying Data in Charts : Previewing data and chart : How to change chart preview preferences
 
How to change chart preview preferences
1 Choose WindowPreferences.
2 Expand Report Design. Select the Chart list item. Expand Chart and Field Assist, as shown in Figure 16‑30. Field Assist and Content Assist preferences include options to flag required fields in the chart builder and to display hints for building an expression
Figure 16‑30 Chart page of Preferences
3 To have the chart builder use randomly selected data in the chart preview window, deselect Enable Live Preview.
4 To set the number of rows that Data Preview displays, type a value in the field.
5 Choose OK.