If you have not already done so, insert a chart by selecting it from the Insert menu, or double-click an existing chart to access the chart's configuration panel.
If you want to disable Tool Tips, clear the Enable check box.
To show the category, series, and/or value in the Tool Tip box, select the respective check boxes.
To show a Tool Tip background in the same color as is set for the series (specified on the Data tab), select the Use Series Color check box.
In the Decimal Places box, enter the number of decimal places for values in the Tool Tips.