diff --git a/src/wireviz/wv_bom.py b/src/wireviz/wv_bom.py
index f780b6b..2a7d485 100644
--- a/src/wireviz/wv_bom.py
+++ b/src/wireviz/wv_bom.py
@@ -17,13 +17,14 @@ BomHash = namedtuple("BomHash", BOM_HASH_FIELDS)
 BomHashList = namedtuple("BomHashList", BOM_HASH_FIELDS)
 PartNumberInfo = namedtuple("PartNumberInfo", "pn manufacturer mpn supplier spn")
 
-BomMode
-"normal"  # no bubbles, full PN info in GV node
-"bubbles"  # = "full" -> maximum info in GV node
-"hide PN info"
-"PN crossref" = "PN bubbles" + "hide PN info"
-"additionally: BOM table in GV graph label (#227)"
-"title block in GV graph label"
+# TODO: different BOM modes
+# BomMode
+# "normal"  # no bubbles, full PN info in GV node
+# "bubbles"  # = "full" -> maximum info in GV node
+# "hide PN info"
+# "PN crossref" = "PN bubbles" + "hide PN info"
+# "additionally: BOM table in GV graph label (#227)"
+# "title block in GV graph label"
 
 
 BomCategory = IntEnum(  # to enforce ordering in BOM
diff --git a/src/wireviz/wv_graphviz.py b/src/wireviz/wv_graphviz.py
index bd5683e..47bafa5 100644
--- a/src/wireviz/wv_graphviz.py
+++ b/src/wireviz/wv_graphviz.py
@@ -142,6 +142,8 @@ def bom_bubble(id) -> Table:
     if id is None:
         return None
     else:
+        # TODO: activate BOM bubbles
+        return None
         # size and style of BOM bubble is optimized to be a rounded square,
         # big enough to hold any two-digit ID without GraphViz warnings
         text = id