How to add row in editable grid?

You can try using in the supporting rule the following structure:
readOnly: ri!index<count(ri!items)
In this way just the last row will remain editable and the previous rows will get disabled

@tanmayab That should be quiet easy. Turn those rows into read only whose index is less than or equal to total length of rows minus 1, and this also takes care of the exclusion of the last row. Perform this operation under the saveInto that will be executed when '+' link is clicked.

But we need to focus on one thing - will the last row always stay in a editable mode? If not, are you able to handle the condition of turning the last row into read only mode after the completion of editing the last row, that is are you able to decide when the editing of last row is complete? Consider this only when you want to turn the last row into read only mode after editing it.

Now I am able to make it disabled ..Thanks a lot @mihaioctaviant and @sikhivahans