     switch
       # if this is first message put a date marker no matter what.
       when not prevMessage
-        markers.push <DateMarker date={currentMessage.get 'createdAt'} />
+        markers.push \
+          <DateMarker
+            key={currentMessage.get 'createdAt'}
+            date={currentMessage.get 'createdAt'} />
 
       # if day of previous message is not the same with current one, put a date
       # marker.
       when not currentMessageMoment.isSame prevMessageMoment, 'day'
-        markers.push <DateMarker date={currentMessage.get 'createdAt'} />
+        markers.push \
+          <DateMarker
+            key={currentMessage.get 'createdAt'}
+            date={currentMessage.get 'createdAt'} />
 
     # put new message marker on top of other messages if unread count is
     # greater than currently loaded messages.

      if afterMarker = loaderMarkers.get 'after'
        markers.push \
          <LoadMoreMessagesMarker
            channelId={channelId}
            messageId={currentMessage.get 'id'}
            position="after"

      if beforeMarker = loaderMarkers.get 'before'
        markers.push \
          <LoadMoreMessagesMarker
            key="loadafter-#{currentMessage.get 'id'}"
            channelId={channelId}
            messageId={currentMessage.get 'id'}
            position="before"
