DataGridView adding new row problem

Windows Forms .Net framework 4.0

Hi everybody,

I have a problem in the datagridview, while data entry I have two scenarios, the problem is in one of these two scenarios:

1st scenario: Entering data by typing the values in the grid cells, then automatically a new row at the bottom of the datagridview is created.

2nd scenario: Entering data using Lookup functionality so that by double click on the cell, then a lookup Form appears and select from the value that will be filled into the cell was double clicked in our grid. In the current scenario the problem occurs, were no new row is created since there is no manual edit done on any cell on the active row.

How to solve this problem???