diff --git a/bt5/erp5_wendelin/DocumentTemplateItem/portal_components/document.erp5.DataArray.py b/bt5/erp5_wendelin/DocumentTemplateItem/portal_components/document.erp5.DataArray.py
index 93f8a1204a31bf76105b7d6578fd2fe39cd17d5c..0dec8d84049bd38431a41cfd621c6fa7f2871cca 100644
--- a/bt5/erp5_wendelin/DocumentTemplateItem/portal_components/document.erp5.DataArray.py
+++ b/bt5/erp5_wendelin/DocumentTemplateItem/portal_components/document.erp5.DataArray.py
@@ -106,6 +106,8 @@ class DataArray(BigFile):
 
     return ''
 
+  # FIXME this duplicates a lot of code from ERP5's BigFile
+  # -> TODO reuse BigFile streaming capability without copying its code
   def _range_request_handler(self, REQUEST, RESPONSE):
     RESPONSE.setHeader("Content-Type", "application/octet-stream")
     # HTTP Range header handling: return True if we've served a range