You can cancel the default action for a HtmlElement.MouseDown event on an element by setting the HtmlElementEventArgs.ReturnValue property of the System.Windows.Forms.HtmlElementEventArgs class to true.

A HtmlElement.MouseDown event on an element will also occur on that element's parent elements and on the System.Windows.Forms.HtmlDocument class itself, unless you set the HtmlElementEventArgs.BubbleEvent property of the System.Windows.Forms.HtmlElementEventArgs class to true.

For more information about the difference between canceling event bubbling and canceling the default action on an event, see tp://msdn.microsoft.com/en-us/library/ms533022.aspx.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
Assembly Versions: 2.0.0.0