diff --git a/doc/README.dissector b/doc/README.dissector
index 36367696ff..17b3273336 100644
--- a/doc/README.dissector
+++ b/doc/README.dissector
@@ -112,11 +112,18 @@ FIELDTYPE       FT_NONE, FT_BOOLEAN, FT_UINT8, FT_UINT16, FT_UINT24,
                 FT_IPv6, FT_IPXNET, FT_FRAMENUM, FT_PROTOCOL, FT_GUID, FT_OID,
                 FT_REL_OID, FT_AX25, FT_VINES, FT_SYSTEM_ID, FT_FC, FT_FCWWN
 FIELDDISPLAY    --For FT_UINT{8,16,24,32,40,48,56,64} and
-                      FT_INT{8,16,24,32,40,48,56,64):
+                       FT_INT{8,16,24,32,40,48,56,64):
 
                   BASE_DEC, BASE_HEX, BASE_OCT, BASE_DEC_HEX, BASE_HEX_DEC,
-                  or BASE_CUSTOM, possibly ORed with BASE_RANGE_STRING,
-                  BASE_EXT_STRING or BASE_VAL64_STRING
+                  BASE_CUSTOM, or BASE_NONE, possibly ORed with
+                  BASE_RANGE_STRING, BASE_EXT_STRING or BASE_VAL64_STRING.
+
+                  BASE_NONE may be used with a non-NULL FIELDCONVERT when the
+                  numeric value of the field itself is not of significance to
+                  the user (for example, the number is a generated field).
+                  When this is the case the numeric value is not shown to the
+                  user in the protocol decode nor is it used when preparing
+                  filters for the field in question.
 
                 --For FT_UINT16:
 
diff --git a/epan/expert.c b/epan/expert.c
index c4d106e7f6..b45541da2e 100644
--- a/epan/expert.c
+++ b/epan/expert.c
@@ -205,10 +205,10 @@ expert_packet_init(void)
 			{ "Message", "_ws.expert.message", FT_STRING, BASE_NONE, NULL, 0, "Wireshark expert information", HFILL }
 		},
 		{ &hf_expert_group,
-			{ "Group", "_ws.expert.group", FT_UINT32, BASE_HEX, VALS(expert_group_vals), 0, "Wireshark expert group", HFILL }
+			{ "Group", "_ws.expert.group", FT_UINT32, BASE_NONE, VALS(expert_group_vals), 0, "Wireshark expert group", HFILL }
 		},
 		{ &hf_expert_severity,
-			{ "Severity level", "_ws.expert.severity", FT_UINT32, BASE_HEX, VALS(expert_severity_vals), 0, "Wireshark expert severity level", HFILL }
+			{ "Severity level", "_ws.expert.severity", FT_UINT32, BASE_NONE, VALS(expert_severity_vals), 0, "Wireshark expert severity level", HFILL }
 		}
 	};
 	static gint *ett[] = {
diff --git a/epan/proto.c b/epan/proto.c
index aa457649b3..268e443221 100644
--- a/epan/proto.c
+++ b/epan/proto.c
@@ -6526,12 +6526,16 @@ tmp_fld_check_assert(header_field_info *hfinfo)
 				wmem_free(NULL, tmp_str);
 				break;
 			}
+
 			/*  Require integral types (other than frame number,
 			 *  which is always displayed in decimal) to have a
 			 *  number base.
-			 *  If there is a strings value then this base is not
-			 *  normally used except when constructing a display
-			 *  filter for a value not found in the strings lookup.
+			 *
+			 *  If the display value is BASE_NONE and there is a
+			 *  strings conversion then the dissector writer is
+			 *  telling us that the field's numerical value is
+			 *  meaningless; we'll avoid showing the value to the
+			 *  user.
 			 */
 			switch (hfinfo->display & FIELD_DISPLAY_E_MASK) {
 				case BASE_DEC:
@@ -6541,6 +6545,14 @@ tmp_fld_check_assert(header_field_info *hfinfo)
 				case BASE_HEX_DEC:
 				case BASE_CUSTOM: /* hfinfo_numeric_value_format() treats this as decimal */
 					break;
+				case BASE_NONE:
+					if (hfinfo->strings == NULL)
+						g_error("Field '%s' (%s) is an integral value (%s)"
+							" but is being displayed as BASE_NONE but"
+							" without a strings conversion",
+							hfinfo->name, hfinfo->abbrev,
+							ftype_name(hfinfo->type));
+					break;
 				default:
 					tmp_str = val_to_str_wmem(NULL, hfinfo->display, hf_display, "(Unknown: 0x%x)");
 					g_error("Field '%s' (%s) is an integral value (%s)"