zenity - multi menu

#! /bin/bash


while true; do
  choice="$(zenity --width=200 --height=150 --list --column "" --title="test" \
  "Go to next menu" \
  "Exit ")"

  case "${choice}" in
    "Go to next menu" )
      while true; do
        choice2="$(zenity --width=200 --height=150 --list --column "" --title="test" \
        "Do Something" \
        "Do Something Else " \
        "Back")"

        case "${choice2}" in
          "Do Something" )
            echo "hello"
          ;;
          "Do Something Else " )
            echo "hello"
          ;;
          *)
            break
          ;;
        esac
      done
    ;;
    *)
      break
    ;;
  esac
done