Indicate unread if there is a message on disk and there is no specifi…

…ed read marker.

data/src/history.rs

@@ -221,10 +221,11 @@ impl History {
             } => {
                 // Read marker is prior to last message on disk
                 // or prior to unflushed messages in memory
-                last_on_disk
-                    .zip(metadata.read_marker)
-                    .map_or(false, |(a, b)| a > b.date_time())
-                    || metadata.unread_count(messages) > 0
+                last_on_disk.zip(metadata.read_marker).map_or(
+                    last_on_disk.is_some() && metadata.read_marker.is_none(),
+                    |(a, b)| a > b.date_time(),
+                ) || metadata.unread_count(messages) > 0
+            }
             }
             History::Full { .. } => false,
         }