This is only reproducible with 9 b45. It works fine with 8u40 b20.

Steps to reproduce:
Run attached program.
1. Select the cell at (0,0)
2. Press Shift + Right arrow key, util the last cell of the row is selected.
3. Press Shift + Right arrow key again, the last cell is unselected.
4. Keep pressing Shift + Right, the selection status of the last cell is looping.

In Step 3, the last cell should not be unselected by Shift + Right, it should be kept being selected.