When using fine-tune for rubric grading, if the instructor clicks in a cell, the score (adding/subtracting) should start with the score from the cell

Using Firefox or Chrome, create a rubric. Click on Gradebook -> Add Gradebook Item Fill out the item, add the rubric, and select "Fine tune criterion point values ".  Save the item. Click to grade the rubric for one of the students (drop-down in the cell beside student name) Click in one of the cells with a point value (e.g. 5) Using the arrows in the last column, click up/down to modify the score. Expected behavior: if the 5 point cell was clicked, the last column displays 5, then clicking up/down to increase/decrease the points should start with 5, not 0.