How to show window contents while dragging

Here's how to enable or disable the "Show window contents while dragging" Windows fature from Delphi code:

//To Show window contents while dragging:
SystemParametersInfo(SPI_SETDRAGFULLWINDOWS, 1, nil, 0) ;

//To disable this option call the function:
SystemParametersInfo(SPI_SETDRAGFULLWINDOWS, 0, nil, 0) ;