function SetFormTransparent(AFormHandle: HWnd; ATransparentVal: Byte): Boolean;
const
  WS_EX_LAYERED = $00080000;
  LWA_ALPHA = $00000002;
var LStyle: Integer;
    LDLLHandle: Cardinal;
    LSetLayerdProc: function (Hwnd: THandle; crKey: COLORREF; bAlpha: Byte; dwFlags: DWORD): Boolean; stdcall;
begin
  LDLLHandle := LoadLibrary('user32.dll');
  if LDLLHandle <> 0 then
  begin
    @LSetLayerdProc := GetProcAddress(LDLLHandle, 'SetLayeredWindowAttributes');
    if Assigned(LSetLayerdProc) then
    begin
      LStyle := GetWindowLong(AFormHandle, GWL_EXSTYLE);
      SetWindowLong(AFormHandle, GWL_EXSTYLE, LStyle or WS_EX_LAYERED);

      result := LSetLayerdProc(AFormHandle, 0, ATransparentVal, LWA_ALPHA);
    end else result := False;
    FreeLibrary(LDLLHandle);
  end else result := False;
end;