Virtual keyboard not displaying with UI element (OVR 1.70.0)

I'm programmatically displaying the keyboard according to the keyboard overlay developer document. But, once the keyboard is displayed and DONE is pressed, the app loses focus forever. Pressing the menu button on the right controller causes the app to close and returns me to the main menu.

Here's my code for the text input in the GUI canvas in an attempt to programmatically display an on-screen keyboard.

using UnityEngine;
using UnityEngine.UI;

namespace MainMenu {

  public class tbIPAddress : MonoBehaviour {

    TouchScreenKeyboard _key;

    void Start() {

      GetComponent<InputField>().text = Assets.StaticVariables._IP_ADDRESS;

      GetComponent<InputField>().onValueChanged.AddListener(saveValue);
    }

    private void OnDestroy() {

      if (_key != null && _key.active)
        _key.active = false;

      GetComponent<InputField>().onValueChanged.RemoveAllListeners();
    }

    void saveValue(string v) {

      Assets.StaticVariables._IP_ADDRESS = v;
    }

    private void Update() {

      var tb = GetComponent<InputField>();

      if (tb.isFocused && (_key == null || !_key.active))
        _key = TouchScreenKeyboard.Open(Assets.StaticVariables._IP_ADDRESS, TouchScreenKeyboardType.DecimalPad);

      if (_key != null && _key.active)
        tb.text = _key.text;
    }
  }
}