I added a new field "Global: Math expression" to a view using the 'old' UI. It worked well.
Then I updated to a Views version with new UI. Now, when I edit the field, the layover 'Configure field: Global: Math expression' is empty, so I cannot edit the contents. The same goes when i add a new field. I am using:
ctools 7.x-1.x-dev (2011-Mar-27)
views 7.x-3.x-dev (2011-Mar-30)