Vaadin grid, double clicking last row creating duplicate row above

Hi,
I am using vaadin version 7.6.1 and currently using the grid component. I am facing a strange problem now. If I am double clicking on the last row for editing, it just creates a duplicate of the clicked row some where above and there only we are able to edit.

All other rows have editable row in the same row itself and the grid's save and cancel button comes below.

Not sure if its a bug.

Thank you.