diff --git a/static/js/emailLibrary.js b/static/js/emailLibrary.js
index 3747db411..e69f22680 100644
--- a/static/js/emailLibrary.js
+++ b/static/js/emailLibrary.js
@@ -436,18 +436,18 @@ function _hasDesktopRoomForEmailAndDocument(modal, opts = {}) {
 function _prepareEmailWindowForDocument(modal) {
   if (window.innerWidth <= 768) return true;
   if (!modal) return false;
+  // Try to make breathing room by collapsing the wide sidebar to the rail
+  // when there isn't enough horizontal space for both panes. The
+  // route-collapse marker that collapseSidebarToRail() sets means the
+  // sidebar will auto-restore when the doc closes. Crucially, we no
+  // longer fall back to clearing the split when even that isn't enough —
+  // the user opted out of auto-tab-down, so we proceed with the dock
+  // even if it's cramped.
   if (!_hasDesktopRoomForEmailAndDocument(modal)) {
-    // Before giving up and minimizing email, see if collapsing the wide
-    // sidebar to the rail would recover enough space. The route-collapse
-    // marker that collapseSidebarToRail() sets makes the existing
-    // auto-restore logic put the sidebar back when the doc closes.
     const sidebar = document.getElementById('sidebar');
     const sidebarWasOpen = sidebar && !sidebar.classList.contains('hidden');
     if (sidebarWasOpen && _hasDesktopRoomForEmailAndDocument(modal, { assumeSidebarCollapsed: true })) {
       try { collapseSidebarToRail(); } catch (_) {}
-    } else {
-      _clearEmailDocumentSplit();
-      return true;
     }
   }
   if (modal.classList.contains('modal-left-docked')) {