Hi, I am using masking for a text field to restrict it to 16 characte

Just to add to my solution. When you are on a specific row in a grid the compentDom that gets passed in is that specific field in the column so it only validates that field. However when the form is submitted if there is an error on one of the rows in the column the entire column will show in a pink tint but the row with the error should be the only one with an exclamation point.

You can also edit that function to have your masking that you want instead of just checking for length.