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matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/timeline/TimelineEvent.kt

@@ -38,6 +38,9 @@ import org.matrix.android.sdk.api.util.ContentUtils.extractUsefulTextFromReply
  */
 data class TimelineEvent(
         val root: Event,
+        /**
+         * Uniquely identify an event, computed locally by the sdk
+         */
         val localId: Long,
         val eventId: String,
         val displayIndex: Int,

vector/src/main/java/im/vector/app/features/home/room/detail/timeline/TimelineEventController.kt

@@ -427,6 +427,7 @@ class TimelineEventController @Inject constructor(private val dateFormatter: Vec
             val formattedDayModel: DaySeparatorItem? = null
     ) {
         fun shouldTriggerBuild(): Boolean {
+            // Since those items can change when we paginate, force a re-build
             return mergedHeaderModel != null || formattedDayModel != null
         }
     }