Index: trunk/FACT++/src/fitsdump.cc
===================================================================
--- trunk/FACT++/src/fitsdump.cc	(revision 14885)
+++ trunk/FACT++/src/fitsdump.cc	(revision 14929)
@@ -879,5 +879,6 @@
         "In --root mode, fitsdump support TFormula's syntax for all columns and the filter "
         "You can then refer to a column or a (single) index of the column just by its name "
-        "If the index is omitted, 0 is assumed\n"
+        "If the index is omitted, 0 is assumed. Note that the [x:y] syntax in this mode is "
+        "not supported\n"
         "\n"
         "  fitsdump Zd --filter=\"[0]>20 && cos([1])*TMath::RadToDeg()<45\"\n"