**I'm still using 2017.1, apologies if this has been resolved in a later version**
Currently when you use AttributeValueMapper, the import allows you to import duplicate values rather than check if you've already got the value and mapped it in the transformer. Can this be enhanced to recognise the values already mapped rather than keep adding the same value again? Or even better, to enable you to sort on the 'Source Value' field?
For Example, I'm consolidating a few datasets in FME hence might use the import feature twice once for a shapefile, another for a KML. I have High=1, Medium=2, Low=3 imported and mapped from the shp, then import the values from KML and get High (already exists), Very Low (new), Medium (already exists).