diff --git a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip29RelayGroups/GroupScope.kt b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip29RelayGroups/GroupScope.kt
index fd88ddf8b0..cb349e3efd 100644
--- a/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip29RelayGroups/GroupScope.kt
+++ b/quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip29RelayGroups/GroupScope.kt
@@ -20,6 +20,7 @@
  */
 package com.vitorpamplona.quartz.nip29RelayGroups
 
+import com.vitorpamplona.quartz.buzz.stream.StreamMessageV2Event
 import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip01Core.core.TagArray
 import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
@@ -69,6 +70,9 @@ fun Event.isGroupScoped(): Boolean = groupId() != null
  * to my group message is group-scoped too, so without this distinction it would be
  * picked as the group's "last message" and render as a bogus, unopenable row on the
  * Messages tab. Content kinds: 9 ([ChatEvent]), 1068 ([PollEvent]), 11
- * ([ThreadEvent]), 1111 ([CommentEvent]).
+ * ([ThreadEvent]), 1111 ([CommentEvent]), and 40002 ([StreamMessageV2Event]) — the
+ * Buzz dialect's stream-channel chat message, which is `h`-scoped and attaches to the
+ * same channel as a kind-9, so it must count as a room's newest message too (otherwise
+ * a Buzz channel's Messages-list preview and unread dot never reflect its real chat).
  */
-fun Event.isGroupChatContent(): Boolean = this is ChatEvent || this is PollEvent || this is ThreadEvent || this is CommentEvent
+fun Event.isGroupChatContent(): Boolean = this is ChatEvent || this is PollEvent || this is ThreadEvent || this is CommentEvent || this is StreamMessageV2Event
diff --git a/quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip29RelayGroups/Nip29ArmadaInteropTest.kt b/quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip29RelayGroups/Nip29ArmadaInteropTest.kt
index 33703c3ae3..90daa6bd0b 100644
--- a/quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip29RelayGroups/Nip29ArmadaInteropTest.kt
+++ b/quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip29RelayGroups/Nip29ArmadaInteropTest.kt
@@ -20,6 +20,7 @@
  */
 package com.vitorpamplona.quartz.nip29RelayGroups
 
+import com.vitorpamplona.quartz.buzz.stream.StreamMessageV2Event
 import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
 import com.vitorpamplona.quartz.nip22Comments.CommentEvent
@@ -253,6 +254,26 @@ class Nip29ArmadaInteropTest {
         assertEquals(gid, react.groupId())
     }
 
+    @Test
+    fun buzzStreamMessageCountsAsGroupChatContent() {
+        // A kind-9 chat message is group content.
+        val kind9 = parse(ChatEvent.KIND, arrayOf(arrayOf("h", gid)), content = "gm", pubKey = alice)
+        assertTrue(kind9.isGroupChatContent())
+
+        // A Buzz stream-channel chat message (kind 40002) is `h`-scoped and attaches to the same
+        // RelayGroupChannel as a kind-9, so it must count as a room's newest message too — otherwise
+        // a Buzz channel's Messages-list preview and unread dot never reflect its real chat.
+        val buzz = parse(StreamMessageV2Event.KIND, arrayOf(arrayOf("h", gid)), content = "hi from buzz", pubKey = alice)
+        assertTrue(buzz is StreamMessageV2Event)
+        assertEquals(gid, buzz.groupId())
+        assertTrue(buzz.isGroupChatContent())
+
+        // A reaction is group-scoped but NOT content — it must never become a room's last message.
+        val react = parse(ReactionEvent.KIND, arrayOf(arrayOf("h", gid), arrayOf("e", "ee".repeat(32))), content = "🔥", pubKey = alice)
+        assertTrue(react.isGroupScoped())
+        assertFalse(react.isGroupChatContent())
+    }
+
     @Test
     fun ungroupedEventHasNoGroupId() {
         val e = parse(ChatEvent.KIND, arrayOf(arrayOf("t", "hi")), content = "hi", pubKey = alice)