1 files changed, 8 insertions, 4 deletions
diff --git a/src/feed-window.js b/src/feed-window.js
index 88170be..6d351f4 100644
--- a/src/feed-window.js
+++ b/src/feed-window.js
@@ -1,6 +1,6 @@
 // Merge prepared events without inserting between visible posts or evicting
 // the reading position. Row geometry comes from the currently rendered feed.
-export function mergeFeedWindow(notes, shown, additions, { rows = [], height = 0, keep = 200, page = 20 } = {}) {
+export function mergeFeedWindow(notes, shown, additions, { rows = [], height = 0, keep = 200, page = 20, holdHead = false } = {}) {
   const byId = new Map(rows.map((r) => [r.id, r]));
   const first = rows.find((r) => r.bottom > 0 && r.top < height);
   const seen = new Set(notes.map((e) => e.id));
@@ -12,9 +12,13 @@ export function mergeFeedWindow(notes, shown, additions, { rows = [], height = 0
     // locating the next rendered post: they cannot serve as an anchor.
     const next = notes.find((n) => n.created_at < e.created_at && byId.has(n.id));
     const row = next && byId.get(next.id);
-    // Even a prepend must wait while the header is visible: anchoring just
-    // the first post would scroll the header away.
-    const inView = row && row.top < height && (row === first ? row.top > 0 : row.top >= 0);
+    // Above the first post on screen is fine even with the header showing:
+    // that post is held where it is and the header goes up with the rest,
+    // so the scrollbar shows there's more above without anything you're
+    // reading moving. holdHead (someone is writing up there) keeps the old
+    // rule, so the composer isn't scrolled out from under a typing thumb.
+    const inView = row && row.top < height
+      && (row === first ? holdHead && row.top > 0 : row.top >= 0);
     (inView ? deferred : added).push(e);
   }
   if (!added.length) return { notes, shown, added, deferred };