dont scroll to first item, it obscures back button

routes/_components/pseudoVirtualList/PseudoVirtualListLazyItem.html

@@ -4,7 +4,6 @@
                          :key
                          :index
                          :length
-                         :scrollToThisItem
                          :intersectionObserver
                          :isIntersecting
                          :isCached

routes/_components/timeline/Timeline.html

@@ -37,7 +37,7 @@
                        items="{{$timelineItemIds}}"
                        shown="{{$initialized}}"
                        on:initializedVisibleItems="initialize()"
-                       scrollToItem="{{timelineValue}}"
+                       scrollToItem="{{scrollToItem}}"
                        realm="{{$currentInstance + '/' + timeline}}"
     />
   {{/if}}
@@ -115,9 +115,17 @@
       timelineValue: (timeline) => {
         return timeline.split('/').slice(-1)[0]
       },
-      // for threads, it's simpler to just render all items due to need to scroll to the right item
-      // TODO: this can be optimized to use a virtual list
-      virtual: (timelineType) => timelineType !=='status'
+      // for threads, it's simpler to just render all items as a pseudo-virtual list
+      // due to need to scroll to the right item and thus calculate all item heights up-front
+      virtual: (timelineType) => timelineType !=='status',
+      scrollToItem: (timelineType, timelineValue, $firstTimelineItemId) => {
+        // Scroll to the first item if this is a "status in own thread" timeline.
+        // Don't scroll to the first item because it obscures the "back" button.
+        return timelineType === 'status'
+          && $firstTimelineItemId
+          && timelineValue !== $firstTimelineItemId
+          && timelineValue
+      }
     },
     store: () => store,
     components: {

routes/_store/timelineComputations.js

@@ -16,5 +16,6 @@ export function timelineComputations (store) {
   computeForTimeline(store, 'lastFocusedElementSelector')
   computeForTimeline(store, 'ignoreBlurEvents')
 
+  store.compute('firstTimelineItemId', ['timelineItemIds'], (timelineItemIds) => timelineItemIds && timelineItemIds.length && timelineItemIds[0])
   store.compute('lastTimelineItemId', ['timelineItemIds'], (timelineItemIds) => timelineItemIds && timelineItemIds.length && timelineItemIds[timelineItemIds.length - 1])
 }