To edit table cells, select Cell from the drop-down menu and choose the action you would like to take.
You can Insert Cell Before or After selected cells, Delete Cells, or Merge Cells.
To Paste content you have saved in your clipboard into a table, right-click (or CTRL-click on a Mac) in the table cell where you would like to paste the content, and select Paste from the drop-down menu.
This will lead to problems like "Grid View does not show updated values", "Grid View looses values changed by user". In your Page_load, this is typically only inside a block where you check to make sure that Page_Load is not being called during a post-back call.