diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -373,7 +373,10 @@
 }
 
 function threadIsPendingSidebar(threadID: ?string): boolean {
-  return !!threadID?.startsWith('pending/sidebar/');
+  return (
+    !!threadID?.startsWith('pending/sidebar/') ||
+    !!threadID?.startsWith('pending/dm_sidebar')
+  );
 }
 
 function getSingleOtherUser(
diff --git a/lib/shared/thread-utils.test.js b/lib/shared/thread-utils.test.js
--- a/lib/shared/thread-utils.test.js
+++ b/lib/shared/thread-utils.test.js
@@ -4,6 +4,7 @@
   parsePendingThreadID,
   threadInfoFromRawThreadInfo,
   getPendingThreadID,
+  threadIsPendingSidebar,
 } from './thread-utils.js';
 import { threadInfoValidator } from '../permissions/minimally-encoded-thread-permissions-validators.js';
 import type { RawThreadInfo } from '../types/minimally-encoded-thread-permissions-types.js';
@@ -213,3 +214,28 @@
     ).toStrictEqual('pending/dm_sidebar/12345');
   });
 });
+
+describe('threadIsPendingSidebar', () => {
+  it('should correctly check if sidebar is pending', () => {
+    const thinPendingSidebarID = getPendingThreadID(
+      threadTypes.SIDEBAR,
+      [],
+      '12345',
+    );
+    const thickPendingSidebarID = getPendingThreadID(
+      threadTypes.THICK_SIDEBAR,
+      [],
+      '12345',
+    );
+    const nonSidebarPendinThreadID = getPendingThreadID(
+      threadTypes.PERSONAL,
+      [],
+    );
+
+    expect(threadIsPendingSidebar(thinPendingSidebarID)).toStrictEqual(true);
+    expect(threadIsPendingSidebar(thickPendingSidebarID)).toStrictEqual(true);
+    expect(threadIsPendingSidebar(nonSidebarPendinThreadID)).toStrictEqual(
+      false,
+    );
+  });
+});