Destroy monaco if you can. Edit if files opened.

app/assets/javascripts/repo/components/repo_edit_button.vue

@@ -11,7 +11,7 @@ export default {
     },
 
     showButton() {
-      return this.isCommitable && !this.activeFile.render_error && !this.binary;
+      return this.isCommitable && !this.activeFile.render_error && !this.binary && this.openedFiles.length;
     }
   },
   methods: {

app/assets/javascripts/repo/components/repo_editor.vue

@@ -8,7 +8,9 @@ const RepoEditor = {
   data: () => Store,
 
   destroyed() {
-    this.monacoInstance.destroy();
+    if(this.monacoInstance){
+      this.monacoInstance.destroy();
+    }
   },
 
   mounted() {