TClrCustomControl.CreateControl Method
Forces the creation of the visible control, including the creation of the handle and any visible child controls.
The CreateControl method forces a handle to be created for the
control and its child controls. This method is used when you need a
handle immediately for manipulation of the control or its children;
simply calling a control's constructor does not create the Handle.
CreateControl does not create a control handle if the control's
Visible property is false. You can either call the CreateHandle method or access the Handle property to create the
control's handle regardless of the control's visibility, but in this
case, no window handles are created for the control's children.