Delete row in Master Detail Display

Hi every one
I don’t know if this is a bug or I make an error

if i choose (List Page) and from (List - Page properties) from (01-Pag Design)
then (Display Template) and make (Multi Select Checkbox) = False
then go to (Master Detail Display) when I make it true

and run the project and click the triangle of master detail display it show delete this row (it will apper next to print icon) …!!

I checked it with react and it is the same !!