diff --git a/R/bio/diffex_commons.R b/R/bio/diffex_commons.R
index e618575630a2dfd7690c12949343c9aa78ef0068..4e5c230e38132744cd67a7014242a614b9f3b0aa 100644
--- a/R/bio/diffex_commons.R
+++ b/R/bio/diffex_commons.R
@@ -170,6 +170,13 @@ davidAnnotationChart <- function( someGenes, ontologies=DEF_DAVID_ONTOLOGIES ){
 
     unloadNamespace('RDAVIDWebService')
 
-    return(annoChart %>% subset(select=-Genes))
+    ## remove gene colum
+#    browser()
+    annoChart <- as.data.frame(unclass(annoChart))
+
+    # http://stackoverflow.com/questions/25271856/cannot-coerce-class-typeof-is-double-to-a-data-frame
+    if(nrow(annoChart) >0) annoChart <-  annoChart %>%  dplyr::select(select=-Genes)
+
+    return(annoChart)
 }