$mw->Label(-text=>"level1 ")->grid(
      $mw->Optionmenu(-textvariable=>\$selectedDir,
           -command=>
     sub{ @files=`ls $path/$selectedDir`;       
             foreach (@files) {chomp();} },
               -options=>\@myArr),

      $mw->Label(-text=>"level2 "),
      $mw->Optionmenu(-textvariable=>\$myFile,
                  -options=>\@files)
                                  );