Gets the help url of the command that raised this event.
Namespace: Rhino.Commands
Assembly: RhinoCommon (in RhinoCommon.dll)
**Since:**8.0
public string CommandHelpURL { get; }
Type:String
Null is a possible return. Calling function must check before using result. m_help_url will get set only if the commmand has a ContextHelpURL override.