Tool-tips are short text messages displayed when the mouse pointer hovers over a diagram item for a while. To enable tool-tips, set the ShowToolTips property to true. The delay before a tool-tip appears is set via the ToolTipDelay property.

Tool-tips can be defined for each diagram element and for the whole document. If the mouse pointer stands still and it points to an item, then the ToolTip of the item is displayed. The ToolTip of the diagram appears if there is no item under the cursor or if there is an item but there isn't any tool-tip text defined for it. The anchor points assigned to nodes also provide a ToolTip property.

Tool-tip's text is also used as a value of the ALT attribute of image map areas corresponding to items; see HtmlBuilder for more information.