stop assuming leftRibbon is always there

main.js

@@ -25,12 +25,21 @@ module.exports = class RibbonOrderLock extends Plugin {
 
   onunload() {
     this.observer?.disconnect();
-    this.app.workspace.leftRibbon.onChange = this.originalOnChange;
+    const ribbon = this.getRibbon();
+    if (ribbon) {
+      ribbon.onChange = this.originalOnChange;
+    }
+  }
+
+  getRibbon() {
+    return this.app.workspace.leftRibbon ?? null;
   }
 
   observeRibbon() {
-    const ribbon = this.app.workspace.leftRibbon;
+    const ribbon = this.getRibbon();
+    if (!ribbon) return;
     const containerEl = ribbon.ribbonItemsEl;
+    if (!containerEl) return;
 
     this.observer = new MutationObserver(() => this.debouncedEnforce());
     this.observer.observe(containerEl, { childList: true });
@@ -39,7 +48,8 @@ module.exports = class RibbonOrderLock extends Plugin {
   // hook the ribbon's own onChange so drags and hide/show toggles update
   // our saved order automatically, same as Obsidian's native reorder does
   patchRibbon() {
-    const ribbon = this.app.workspace.leftRibbon;
+    const ribbon = this.getRibbon();
+    if (!ribbon) return;
 
     const original = ribbon.onChange.bind(ribbon);
     this.originalOnChange = original;
@@ -53,7 +63,8 @@ module.exports = class RibbonOrderLock extends Plugin {
   }
 
   enforceOrder() {
-    const ribbon = this.app.workspace.leftRibbon;
+    const ribbon = this.getRibbon();
+    if (!ribbon) return;
 
     const order = this.settings.order;
     if (order.length === 0) {