It’s not directly intuitive how to do this, since, when you add a label to a form, there is no ‘Tooltip’ property for it.
All you need to do is to drop a ToolTip control from the ToolBox, on your form. It will appear in the tray below the form, and not ON the form itself
Just add a title for it, in the properties of the ToolTip, and then click on the label itself. Now, you will see a ToolTip property in the Properties window. It will say something like ‘ToolTip on ToolTip1′ (Here, ToolTip1 is the Name of the ToolTip in the tray. If you named yours, your specific name should appear here instead)
In this property, just enter the text you want to appear in the ToolTip for the label and you’re done.
All Things DotNet Discussed – Winforms/ASP.Net/SharePoint/WPF