Getting message 'sorting grid data' when making changes in the grid. (4335251)

Getting message 'sorting grid data' when making changes in the grid.
After that happens the only option is to kill Toad.
Steps to reproduce the issue:

1.Make sure the grid option ‘manually submit row changes as a batch’ is checked.
2. Run a query on a table which has a unique column so the grid is edittable.
3. Sort the grid by one column.
4. Update values in that column so the grid re-sorts
5. Click into another cell in the grid.
6. Click the 'Reject' button.

The 'sorting grid data' message box appears and it never closes.
(must kill toad with task manager)