Showing is used internally to optimize the allocation of Windows resources. Use Showing to determine when you must allocate resources that are required when the control is visible. When Showing is false, the control is not visible and you can delay the allocation of resources. 

If the Visible properties of a component and all the parents in its parent hierarchy are true, Showing is guaranteed to be true. If one of the parents containing the control has a Visible property value of false, Showing may be either true or false. 

Showing is a read-only property. 

Visible