Steps to reproduce:
1. On page Group By - move some fields from the dataset to the right table.
2. select an even number of consecutive fields.
3. Press the Down button for rearanging the fields. -> Nothing happens
1.For an even number of selected fields (none of them consecutive), the Down button works ok.
2.For an odd number of consecutive selected fields, just the last one is moved downward when theDown button is pressed.