By default, the item's tooltip is "...". If the ToolTip property is empty, the control displays no tooltip when the cursor hovers the item. If the ToolTip property is "..." the control displays the item's Caption if it doesn't fit the control's client area. Use the GroupToolTip property to specify the tooltip for the group. Use the ToolTipDelay property to specify the time in ms that passes before the ToolTip appears. In this case the control displays no tooltip when the cursor is over the item. Use the ToolTipWidth property to specify the width of the tooltip window. The ToolTip supports built-in HTML format as described here.