diff --git a/turnstone/shared_static/pane.js b/turnstone/shared_static/pane.js
index 3faf5bbe..e5afcbe2 100644
--- a/turnstone/shared_static/pane.js
+++ b/turnstone/shared_static/pane.js
@@ -636,8 +636,12 @@ export class PaneManager {
         const p = this._panes.get(id);
         return id !== keep && p && p.ephemeral;
       });
-    for (const id of doomed) this.close(id); // collapses its cell, then destroys
-    if (this._layout) this._exitLayout(keep); // a close() may have already exited
+    // close() destroys the pane AND renders/persists/notifies; a 2-cell split
+    // fully collapses inside it, so bail before repeating that work.  Only a
+    // 3+-cell split (or an empty doom list) still needs the exit + refresh here.
+    for (const id of doomed) this.close(id);
+    if (!this._layout) return;
+    this._exitLayout(keep);
     this._renderTabs();
     this._persist();
     this._notifyActive();
diff --git a/turnstone/shared_static/shell.css b/turnstone/shared_static/shell.css
index fb9d17e0..9ac2ecaa 100644
--- a/turnstone/shared_static/shell.css
+++ b/turnstone/shared_static/shell.css
@@ -827,11 +827,11 @@
   z-index: 13; /* above the ring overlay — a clean bar, not bar-plus-ring-line */
   pointer-events: none;
 }
-/* per-pane ✕ — on every visible pane.  Split mode: "hide this cell" (the TAB
-   stays — closeCell), but an ephemeral pane (the preview) closes outright;
-   single-pane: "close pane" (withheld from the unclosable Dashboard).  The
-   destructive modes flip the glyph to ✕ and wear .cell-unsplit--close.
-   Shell chrome floating over pane content: elevated panel +
+/* per-pane dismiss chip (.cell-unsplit) — on every visible pane.  Split mode:
+   "−" hides this cell (the TAB stays — closeCell), but an ephemeral pane (the
+   preview) shows "✕" and closes outright; single-pane: "✕" closes the pane
+   (withheld from the unclosable Dashboard).  The destructive "✕" modes wear
+   .cell-unsplit--close.  Shell chrome floating over pane content: elevated panel +
    hairline so it reads as the shell's, not the conversation's; sits clear of
    the 2px focus bar and the cell corner. */
 .cell-unsplit {