From dc1f5bb7b135022ba53f9c8e77eef0498e575ed2 Mon Sep 17 00:00:00 2001
From: Steffen Becker <stffn.becker@gmail.com>
Date: Sun, 16 Aug 2026 01:47:05 +0200
Subject: [PATCH] fix: leaving a header/footer no longer throws
 state_unsafe_mutation

Clearing hfActive removes the live zone's DOM during Svelte's flush;
ProseMirror dispatches a blur transaction as it goes, and the hfTick
mutation in onTransaction then landed mid-render and threw, aborting the
rest of the batch. The tick is queued to the next microtask instead.
---
 src/lib/components/HeaderFooterLayer.svelte | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/lib/components/HeaderFooterLayer.svelte b/src/lib/components/HeaderFooterLayer.svelte
index 8cc7872..9ca168e 100644
--- a/src/lib/components/HeaderFooterLayer.svelte
+++ b/src/lib/components/HeaderFooterLayer.svelte
@@ -337,8 +337,10 @@
       content: (zoneDoc(editingIndex, zone, editingVariant) ?? emptyDoc()) as Content,
       // No autofocus: its scrollIntoView nudges the page so the just-clicked zone
       // appears to jump. Focus the zone explicitly without scrolling instead.
+      // Deferred: leaving a zone removes this DOM mid-render, and the blur ProseMirror
+      // dispatches then would tick state while Svelte is still flushing.
       onTransaction: () => {
-        hfTick++;
+        queueMicrotask(() => hfTick++);
       },
       onUpdate: ({ editor }) => {
         writeZone(editingIndex, zone, editingVariant, editor.getJSON() as HfDoc);