--- a/hgext3rd/evolve/obshistory.py	Sat Jan 11 19:53:11 2020 +0700
+++ b/hgext3rd/evolve/obshistory.py	Tue Jan 14 19:42:06 2020 +0700
@@ -785,8 +785,11 @@
     markers collectively have more than one effect in the flags.
     """
     metadata = [dict(marker[3]) for marker in markers]
+
+    if len(metadata) == 1 and metadata[0].get(b'fold-id') is not None:
+        return b'folded'
+
     ef1 = [data.get(b'ef1') for data in metadata]
-
     if all(ef1):
         combined = 0
         for ef in ef1: