uses

  ..., CommCtrl;

// Способ первый

procedure SetNodeState( node: TTreeNode; Flags: Integer );

var

  tvi: TTVItem;

begin

   FillChar( tvi, SizeOf( tvi ), 0 );

   tvi.hItem := node.ItemID;

   tvi.mask := TVIF_STATE;

   tvi.stateMask := TVIS_CUT;

   tvi.state := Flags;

   TreeView_SetItem( node.Handle, tvi );

end;

procedure TForm1.TreeView1KeyDown(Sender: TObject; var Key: Word;

  Shift: TShiftState);

begin

   // Выделяем бледным

   if ( ssCtrl in Shift ) then

      if ( Key = Ord( 'X' ) ) or ( Key = Ord( 'x' ) ) then

         SetNodeState( ( Sender as TTreeView ).Selected, TVIS_CUT );

   // Снимаем выделение

   if Key = VK_ESCAPE then

      SetNodeState( ( Sender as TTreeView ).Selected, 0 );

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

   TreeView1.Items.Item[0].Cut := true; // false

end;