procedure TForm1.TVMouseMove(Sender: PControl; var Mouse: TMouseEventData);
var
where: DWORD;
begin
TV_Item := TV.TVItemAtPos( Mouse.X, Mouse.Y, where );
end;

procedure TForm1.TVClick(Sender: PObj);
begin
if (GetKeyState(VK_CONTROL) and $80) = $80 then
 Sender.TVItemSelected[TV_Item] := true;
end;