To reproduce:
- add a grid with some sample rows
- apply TelerikMetro theme to the grid
- select the rightmost column
- you will notice that there is 1px extra space between the grid border and the column

Workaround:
- Open the TelerikMetro theme in Visual Style Builder.
- Expand RadGridView up to GridTableElement.
- In the elements window expand TableElement
- Set the padding property to 0.