diff --git a/lib/selectors/chat-selectors.js b/lib/selectors/chat-selectors.js
--- a/lib/selectors/chat-selectors.js
+++ b/lib/selectors/chat-selectors.js
@@ -605,17 +605,47 @@
     return shouldSourceBeAdded ? messageInfos[sourceMessageID] : null;
   });
 
+  // Get the latest edit message to show updated message content
+  // in a pending sidebar
+  const pendingSidebarEditMessageInfo = useSelector(state => {
+    const sourceMessageID = threadInfo?.sourceMessageID;
+    if (!pendingSidebarSourceMessageInfo || !threadInfo) {
+      return null;
+    }
+    const messageInfos = messageInfoSelector(state);
+    const containingThread =
+      state.messageStore.threads[threadInfo.containingThreadID];
+
+    const threadMessageInfos = (containingThread?.messageIDs ?? [])
+      .map((messageID: string) => messageInfos[messageID])
+      .filter(Boolean)
+      .filter(
+        message =>
+          message.targetMessageID === sourceMessageID &&
+          message.type === messageTypes.EDIT_MESSAGE,
+      );
+
+    const result = threadMessageInfos[0];
+    return result ?? null;
+  });
+
   invariant(
     !pendingSidebarSourceMessageInfo ||
       pendingSidebarSourceMessageInfo.type !== messageTypes.SIDEBAR_SOURCE,
     'sidebars can not be created from sidebar_source message',
   );
 
-  const additionalMessages = React.useMemo(
-    () =>
-      pendingSidebarSourceMessageInfo ? [pendingSidebarSourceMessageInfo] : [],
-    [pendingSidebarSourceMessageInfo],
-  );
+  const additionalMessages = React.useMemo(() => {
+    if (!pendingSidebarSourceMessageInfo) {
+      return [];
+    }
+    const result = [pendingSidebarSourceMessageInfo];
+    if (pendingSidebarEditMessageInfo) {
+      result.push(pendingSidebarEditMessageInfo);
+    }
+    return result;
+  }, [pendingSidebarSourceMessageInfo, pendingSidebarEditMessageInfo]);
+
   const boundMessageListData = useSelector(
     messageListData(threadInfo?.id, additionalMessages),
   );