Button disapears from screen problem

I have made repeat order button, but can not test it as it disappears from the screen once I select an item to repeat.
When I select item buttons on the left side changes I get (+) AND (-) buttons show up on the top of the row but my repeat order button disappears as it currently seating on the bottom of the row. Is there option that this button does not despaired or somewhere in settings options on how many buttons can be displayed as I have one more button (Number of guest) that works fine but this repeat order button disappears when item selected and reappears when item unselected?

Map it to order line


Wow thanks a lot, it works, I am just beginner in this but already have learned a lot from your help comments.