roll a ball pickups disappear on full screen

the pickups for roll a ball disappear when i go on to full screen mode, is it just a bug/glitch???

here is my camera script: using System.Collections; using System.Collections.Generic; using UnityEngine;

public class CameraController : MonoBehaviour {

 public GameObject player;

 private Vector3 offset;

 public Transform lookAt;
 public Transform camTransform;

 private Camera cam;

 public const float Y_ANGLE_MIN = 10.0F;
 public const float Y_ANGLE_MAX = 10.0f;

 private float distance = 5.0f;
 public float currentX = 0.0f;
 private float currentY = 0.0f;
 public float sensitivitX = 10.0f;
 public float sensitivityY = 0.0f;

 // Use this for initialization
 void Start() {
     offset = transform.position - player.transform.position;

     camTransform = transform;
     cam = Camera.main;

 }

 private void Update()
 {
     if (Input.GetMouseButton(1))
     {
         currentX += Input.GetAxis("Mouse X");

         currentY += Input.GetAxis("Mouse Y");

         currentY = Mathf.Clamp(currentY, Y_ANGLE_MIN, Y_ANGLE_MAX);
     }
 }

 // Update is called once per frame
 void LateUpdate() {
     transform.position = player.transform.position + offset;
     Vector3 dir = new Vector3(0, 0, -distance);
     Quaternion rotation = Quaternion.Euler(currentY, currentX, 0);
     camTransform.position = lookAt.position + rotation * dir;
     camTransform.LookAt(lookAt.position);
 }
   } 

here is my player script: using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UI;

public class PlayerController : MonoBehaviour { public float currentX = 0.0f;

 public float speed;

 public Text countText;

 public Text winText;

 public int count;

 public float threshold;

 private Rigidbody rb;

 void Start()
 {
     rb = GetComponent<Rigidbody>();
     count =  0;
     SetCountText ();
     winText.text = "";
 }

 void FixedUpdate()
 {
     float moveHorizontal = Input.GetAxis("Horizontal");
     float moveVertical = Input.GetAxis("Vertical");
     currentX += Input.GetAxis("Mouse X");

     Vector3 movementX = Camera.main.transform.right * moveHorizontal;
     Vector3 movementZ = Camera.main.transform.forward * moveVertical;
     Vector3 movement = movementX + movementZ;

     rb.AddForce(movement * speed);

     movement = currentX * movement;

     if (transform.position.y < threshold)
     {
         transform.position = new Vector3(0, 0, 0);
         count = 0;
         SetCountText();
     }
 }

 void OnTriggerEnter(Collider other)
 {
     if (other.gameObject.CompareTag("Pick Up")) {

         other.gameObject.SetActive(false);
         count = count + 1;
         SetCountText();
     }
 }

 void SetCountText ()
 {

     countText.text = "count: " + count.ToString();

     if (count >= 12)
     {
         winText.text = "You Win!!!";
     }
 }

}

can anyone help?

thanks.