Edit > Reorder Attributes
Change the order of custom attributes in the channel box.
Usage
Select one or more attributes in the channel box, and select Edit > Reorder Attributes >
Move Attributes Up or Move Attributes Down.
Note that only user-defined attributes can be reordered.
Tips
Tear off the Reorder Attributes menu to perform multiple quick edits.
Limitations
Duplicating a node after moving attributes sometimes doesn't copy the keyable and channelBox
attribute flags correctly after reordering attributes. This is a known Maya bug. This can be
worked around by saving and reopening the scene first.