This class is the base class for all controls, and as controls are
    windows itself, this class inherits from the TWINDOW class.

    You should keep this in mind, if you are looking into the source
    code for a control. Lets say you want to investigate the TGET class,
    then the actuall class tree would look like:

                  TWINDOW  
                   +- TCONTROL
                       +- TGET


    So a TGET object understands all TCONTROL messages, and because 
    TCONTROL derives from TWINDOW, also all TWINDOW messages.