Exemplo de arraste

{Este exmplo faz que o painel fique com a cor da label que originou o arraste. Somente a Label(Tlabel)
no exemplo as labels devem ter a propriedade DRAGMODE=AUTOMATIC}
procedure TForm1.Panel1DragOver (Sender. Source: TObject; x,y:Integer; State:TDragState; var Accept: Boolean);
begin
Accept:=Source is Tlabel;
end; procedure TForm1.Panel1DragDrop (Sender. Source: TObject; x,y:Integer);
begin
Panel1.color:=(Source as Tlabel).Color;
end;

p.366