From f040d2a047a6764fa5c98a48cecd229dadb275fa Mon Sep 17 00:00:00 2001
From: nesquena-hermes <agent@nesquena-hermes>
Date: Fri, 19 Jun 2026 04:36:39 +0000
Subject: [PATCH] =?UTF-8?q?release:=20v0.51.511=20=E2=80=94=20virtual=20tr?=
 =?UTF-8?q?anscript=20renders=20during=20programmatic=20scrolls=20(#4468)?=
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Fixes a regression from #4434 (v0.51.500). Author (rodboev) gave explicit
go-ahead. Gated earlier: Codex SAFE + Opus SAFE + browser-smoke + suite.

Co-authored-by: rodboev <rodboev@users.noreply.github.com>

Closes #4468
---
 CHANGELOG.md | 6 ++++++
 static/ui.js | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index db1354e3d..123cff3ef 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,12 @@
 
 ## [Unreleased]
 
+## [v0.51.511] — 2026-06-19 — Release RV (virtual transcript renders during programmatic scrolls)
+
+### Fixed
+
+- **Scrolling back down through a long virtualized transcript no longer leaves blank gaps (#4346 family; regression from #4434/v0.51.500).** The message virtual-window render was scheduled behind the scroll handler's `_programmaticScroll` guard, so when the measurement-compensation path adjusted `scrollTop` and briefly left that flag set, scroll events were dropped and the DOM froze (spacer + first row stuck while the computed window advanced). The virtual-window render now always fires on scroll; the guard still suppresses the pin/cue/prefetch bookkeeping that genuinely shouldn't react to programmatic scrolls. Thanks @rodboev.
+
 ## [v0.51.510] — 2026-06-19 — Release RU (Kanban task workspace + dependency controls)
 
 ### Added
diff --git a/static/ui.js b/static/ui.js
index d139a65a2..63b631b37 100644
--- a/static/ui.js
+++ b/static/ui.js
@@ -3657,6 +3657,7 @@ if(typeof window!=='undefined'){
   if(!el) return;
   let _scrollRaf=0;
   el.addEventListener('scroll',()=>{
+    _scheduleMessageVirtualizedRender();
     if(_programmaticScroll) return; // ignore scrolls we triggered ourselves
     _markMessageVirtualScrollActive();
     cancelAnimationFrame(_scrollRaf);
@@ -3693,7 +3694,6 @@ if(typeof window!=='undefined'){
       const showBottomButton=!_scrollPinned && el.scrollHeight-top-el.clientHeight>80;
       _syncScrollToBottomCue(showBottomButton,{newMessage:_newMessageCueVisible});
       if(typeof _updateSessionStartJumpButton==='function') _updateSessionStartJumpButton();
-      _scheduleMessageVirtualizedRender();
       // Prefetch older messages before the reader hits the hard top. Prepending
       // then preserving scrollTop is seamless only if there is runway left for
       // the user's continued upward wheel/touch movement.