Defines the base class for all LCL TComponents including controls
The base class for LCL components associated with widgets.
The widget for this component is derived from WidgetSetClass.
Registers this component class with the current WidgetSet.
This method allows descendents to override the WidgetSetClass.
Registers the class and initializes WidgetSetClass.
TObject.NewInstance
Override this method to remove all references to notification handlers in AnObject.
An override is required as soon as a component allows to add notification handlers. Then all such handlers must be removed, when their owner (AnObject) is destroyed.
The object whose handlers shall be removed.
The number of references to this component.

Which are the possible owners of such references?

Base class for all components having an associated widget.

The widget is created by the LCL control whenever required, and its reference is stored in FReferencePtr. This reference is for internal use by the LCL control, not by application code.

This reference is different from the OS/window manager specific window Handle.

Applications only can send messages to a windowed control, using its window Handle.

can be?

Pointer to a widget class Reference.
Set while we are creating the Reference.
Checks for a valid widget reference.
Override this method to supply specific widget creation parameters.
The parameter record to update.
Destroys the reference object.
Override this method to return the Handle from the reference

what is Handle?

Called after the Reference is created.
Called before the Reference is destroyed
Creates a Reference, if not already done.
Tells the widgetset to create a Reference.
This implementation returns Nil, should be overriden in every derived class.
Tells the widgetset to destroy the Reference.
Get the Handle of this component.
The Handle is sort of pointer or reference, allocated by the operating system or widgetset to this component. A window handle can be used for sending messages to the component.

?

If True, a Reference has been allocated for this component.