you can set DragMode property in inspector.when set it as dgVert,it will can drag vertical,set it as dgHorz,it will can drag Horizontal,set it as dgBoth,it can drag freely.

Also,you can set it by code.

Code example:

procedure TMainFrm.Button1Click(Sender: TObject); 
begin 
  MyCAD1.DragMode:=dgVert; 
  //... 
end;