Set a cell with "Button" cell type, I noticed that the button didn't full fill the cell, there is a little blank space between the button border and cell border, like setting the margin property. The blank space will disappear after the mouse hovering on the cell, see following screenshot, the first "Book Ticket" cell with "Button" cell type is full filled with button after mouse hovering on it.
Hover mouse on this cell
I uploaded the sample for you. Thanks!
Attachment:
Basic_Cell_Type_961ad726.zip