diff --git a/arduino-ide-extension/src/browser/theia/core/application-shell.ts b/arduino-ide-extension/src/browser/theia/core/application-shell.ts
index dd68beeff..eb419dcec 100644
--- a/arduino-ide-extension/src/browser/theia/core/application-shell.ts
+++ b/arduino-ide-extension/src/browser/theia/core/application-shell.ts
@@ -17,6 +17,7 @@ import { Sketch } from '../../../common/protocol';
 import { SaveAsSketch } from '../../contributions/save-as-sketch';
 import { SketchesServiceClientImpl } from '../../../common/protocol/sketches-service-client-impl';
 import { nls } from '@theia/core/lib/common';
+import URI from '@theia/core/lib/common/uri';
 
 @injectable()
 export class ApplicationShell extends TheiaApplicationShell {
@@ -41,6 +42,9 @@ export class ApplicationShell extends TheiaApplicationShell {
       // Make the editor un-closeable asynchronously.
       this.sketchesServiceClient.currentSketch().then((sketch) => {
         if (sketch) {
+          if (!this.isSketchFile(widget.editor.uri, sketch.uri)) {
+              return;
+          }
           if (Sketch.isInSketch(widget.editor.uri, sketch)) {
             widget.title.closable = false;
           }
@@ -49,6 +53,14 @@ export class ApplicationShell extends TheiaApplicationShell {
     }
   }
 
+  private isSketchFile(uri: URI, sketchUriString: string): boolean {
+      const sketchUri = new URI(sketchUriString);
+      if (uri.parent.isEqual(sketchUri)) {
+          return true;
+      }
+      return false;
+  }
+
   async addWidget(
     widget: Widget,
     options: Readonly<TheiaApplicationShell.WidgetOptions> = {}