Only apply the continuation break in the main timeline

Author: robintown

src/components/structures/MessagePanel.tsx

@@ -91,8 +91,9 @@ export function shouldFormContinuation(
         mxEvent.sender.name !== prevEvent.sender.name ||
         mxEvent.sender.getMxcAvatarUrl() !== prevEvent.sender.getMxcAvatarUrl()) return false;
 
-    // Thread summaries should break up a continuation
-    if (threadsEnabled && prevEvent.isThreadRoot) return false;
+    // Thread summaries in the main timeline should break up a continuation
+    if (threadsEnabled && prevEvent.isThreadRoot &&
+        timelineRenderingType !== TimelineRenderingType.Thread) return false;
 
     // if we don't have tile for previous event then it was shown by showHiddenEvents and has no SenderProfile
     if (!haveTileForEvent(prevEvent, showHiddenEvents)) return false;