Error Field is Required : record.Fieldname(124,64)

I designed a custom page and used one record on level 0 and level 1 (Grid) .

After filling all the required fields , when I tried to save the page . I am getting the error " Field is required " .

This field is 1st field in a grid starting from left . If I try to make this field optional and then I will be facing the same error for next required field in the grid .

Solution :

As you can see in above screen shot that I have made level 0 fields editable . Once I make these fields read only and then try to save the page , it will save successfully .