This piece of code shows how to drag a TPanel component Panel1 at run-time:
procedure Form1.MouseDown(Sender: Tobject;
Button: TMouseButton;
Shift: TShiftState;
X, Y: Integer);
const
SC_DragMove = $F012;
begin
ReleaseCapture;
Panel1.Perform(WM_SysCommand, SC_DRAGMOVE, 0);
end;