⤷ Detect a moving form

You must intercept WM_MOVE message.
Implementation of this idea is so:

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
  private
    procedure MyMessage(var Msg: TWMMove); message WM_MOVE;
    { Private declarations }
  public
    { Public declarations }
  end;
...
procedure TForm1.MyMessage(var Msg: TWMMove);
begin
  if Msg.Result=0 then
  begin
    Label1.Caption:='x - '+IntToStr(Msg.XPos);
    Label2.Caption:='y - '+IntToStr(Msg.YPos);
  end;
end;
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