Borderless TForm with drop shadow

Question

I have made a TForm derivative that acts like the drop down part of a combo, or a hint window, or a popup menu - a temporary thing. It has no caption - its BorderStyle is set to

Answer 1

For making drop shadow to work we have to invoke SystemParametersInfo win32 API with SPI_SETDROPSHADOW parameter, to turn on the entire system's drop shadow effect, for more information, please refer to:

SystemParametersInfo