Da musst du die eine Captionzwischenspeichern
Delphi-Quellcode:
procedure TForm1.Button1DragDrop(Sender, Source: TObject; X, Y: Integer);
var a:string;
begin
if (Source is TButton) and (Sender is TButton) then
begin
a:=Button1.caption;
Button1.Caption:= TButton(Source).Caption;
TButton(Source).Caption:=a;
end;
end;
Gruß Matthias
Edit: was vergessen