You are not pressing the check mark button to confirm the edit. I also do not see this on your HUD. To edit with the dedicated button you need to:

1) Press Edit button

2) Use the dedicated button to select boxes

3) Confirm the edit with the checkmark icon that should replace your edit button.

Filmzaza

Confirm edit disappeared after selecting boxes

When you select the button and do you have it selected to display? This is done by making sure it is highlighted green when you select the button and press the back arrow on the top right to adjust the button.