Parsons problem distractors do not show as visible errors when last block

[ascholerChemeketa]

If a distractor in a Parsons problem is in any position BUT the last position, it turns red and shows as a visible error when checked. However, if the distractor is at the end of the solution, nothing is done to highlight it when checked. The problem does not even indicate that the solution is incorrect - just does not respond.

Sample problem. To see error, place blocks in shown order and hit check. Then move x + 1 up a slot or two and check

.. parsonsprob:: sample
    :numbered: left
    :adaptive:

    Add 1 to x and print.
    -----
    x = 10
    =====
    x = x + 1
    ===== 
    print(x)
    ===== 
    x + 1 #distractor