fix(ux): keep sidebar action menu open during chat scroll + close on anchor detach (#5347)

Clean rebase of nankingjing's #5402 (rebase-first).

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

static/sessions.js

@@ -3561,6 +3561,17 @@ function closeSessionActionMenu(){
   _sessionActionSessionId = null;
 }
 
+function _sessionActionMenuShouldIgnoreScrollTarget(target){
+  if(!target || typeof target.closest !== 'function') return false;
+  // #5347: active-chat auto-scroll / manual wheel must not dismiss the sidebar menu.
+  return Boolean(target.closest('#messages, #msgInner, .messages-inner'));
+}
+
+function _sessionActionMenuShouldRepositionOnScroll(target){
+  if(!target || typeof target.closest !== 'function') return false;
+  return Boolean(target.closest('#sessionList, .session-list'));
+}
+
 function _positionSessionActionMenu(anchorEl){
   if(!_sessionActionMenu || !anchorEl) return;
   const rect=anchorEl.getBoundingClientRect();
@@ -4036,6 +4047,15 @@ document.addEventListener('click',e=>{
 document.addEventListener('scroll',e=>{
   if(!_sessionActionMenu) return;
   if(_sessionActionMenu.contains(e.target)) return;
+  if(_sessionActionMenuShouldIgnoreScrollTarget(e.target)) return;
+  if(_sessionActionMenuShouldRepositionOnScroll(e.target) && _sessionActionAnchor){
+    if(!_sessionActionAnchor.isConnected){
+      closeSessionActionMenu();
+      return;
+    }
+    _positionSessionActionMenu(_sessionActionAnchor);
+    return;
+  }
   closeSessionActionMenu();
 }, true);
 document.addEventListener('keydown',e=>{

tests/test_issue5347_sidebar_action_menu_scroll.py

@@ -0,0 +1,33 @@
+"""Regression coverage for #5347: chat scroll must not dismiss sidebar action menu."""
+from pathlib import Path
+
+SESSIONS_JS = (Path(__file__).resolve().parent.parent / "static" / "sessions.js").read_text(encoding="utf-8")
+
+
+def _scroll_listener_block() -> str:
+    marker = "document.addEventListener('scroll',e=>{"
+    start = SESSIONS_JS.find(marker)
+    assert start != -1, "session action menu scroll listener not found"
+    end = SESSIONS_JS.find("}, true);", start)
+    assert end != -1, "session action menu scroll listener did not close"
+    return SESSIONS_JS[start : end + len("}, true);")]
+
+
+def test_chat_scroll_is_ignored_while_session_action_menu_is_open():
+    """Streaming/manual chat scroll must not close the sidebar three-dot menu (#5347)."""
+    block = _scroll_listener_block()
+
+    assert "_sessionActionMenuShouldIgnoreScrollTarget(e.target)" in block
+    assert "#messages" in SESSIONS_JS
+    assert "#msgInner" in SESSIONS_JS
+
+
+def test_session_list_scroll_repositions_instead_of_closing_action_menu():
+    """Sidebar list scroll should keep the menu aligned with its anchor row."""
+    block = _scroll_listener_block()
+
+    assert "_sessionActionMenuShouldRepositionOnScroll(e.target)" in block
+    assert block.index("_sessionActionMenuShouldRepositionOnScroll(e.target)") < block.index(
+        "closeSessionActionMenu();"
+    )
+    assert "_positionSessionActionMenu(_sessionActionAnchor);" in block