Hi, i have found a small problem in gff_filter_by_attribute and not sure how to fix it properly. gff_filter_by_attribute.xml accepts gff data types but crashes if you run it with gff. Because metadata.attribute_types is not defined for gff and the dictionary is empty. For gtf files it works, because gtf has metadata.attribute_types defined. Should we extend the gff data type to also set metadata.attribute_types or is it for some reason better to create a gff<->gtf converter and chance gff_filter_by_attribute.xml to only accept gtf files? Thanks! Bjoern -- Björn Grüning Albert-Ludwigs-Universität Freiburg Institute of Pharmaceutical Sciences Pharmaceutical Bioinformatics Hermann-Herder-Strasse 9 D-79104 Freiburg i. Br. Tel.: +49 761 203-4872 Fax.: +49 761 203-97769 E-Mail: bjoern.gruening@pharmazie.uni-freiburg.de Web: http://www.pharmaceutical-bioinformatics.org/