For some odd reasons, when there are fields with the same display name. e.g. one number field, the other text field. 

In report 2.0, under "show" or "by", there is "T" or "#" label to signal the field type. 
However, not for filter, not in the selection for detailed data table inside of a chart. (also, not in rule engine.) . It's hard to tell part which field I'm selecting. Every time it's a try and error... Just an idea..