diff --git a/extensions/vscode-api-tests/src/singlefolder-tests/notebook.document.test.ts b/extensions/vscode-api-tests/src/singlefolder-tests/notebook.document.test.ts
index 0739e4e8afc..568295ccddf 100644
--- a/extensions/vscode-api-tests/src/singlefolder-tests/notebook.document.test.ts
+++ b/extensions/vscode-api-tests/src/singlefolder-tests/notebook.document.test.ts
@@ -47,10 +47,6 @@ suite('Notebook Document', function () {
 		await utils.closeAllEditors();
 		utils.disposeAll(disposables);
 		disposables.length = 0;
-
-		for (let doc of vscode.notebook.notebookDocuments) {
-			assert.strictEqual(doc.isDirty, false, doc.uri.toString());
-		}
 	});
 
 	suiteSetup(function () {
diff --git a/src/vs/workbench/api/browser/mainThreadNotebookDocuments.ts b/src/vs/workbench/api/browser/mainThreadNotebookDocuments.ts
index bad31cf5a11..f557f5e253d 100644
--- a/src/vs/workbench/api/browser/mainThreadNotebookDocuments.ts
+++ b/src/vs/workbench/api/browser/mainThreadNotebookDocuments.ts
@@ -132,7 +132,17 @@ export class MainThreadNotebookDocuments implements MainThreadNotebookDocumentsS
 		}
 
 		const ref = await this._notebookEditorModelResolverService.resolve(uri, options.viewType);
-		this._modelReferenceCollection.add(ref.object.resource, ref);
+
+		// untitled notebooks are disposed when they get saved. we should not hold a reference
+		// to such a disposed notebook and therefore dispose the reference as well
+		ref.object.notebook.onWillDispose(() => {
+			ref.dispose();
+		});
+
+		// untitled notebooks are dirty by default
+		this._proxy.$acceptDirtyStateChanged(uri, true);
+
+		// apply content changes... slightly HACKY -> this triggers a change event
 		if (options.content) {
 			ref.object.notebook.reset(
 				options.content.cells,
diff --git a/src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts b/src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts
index 7142116ab99..f0051ae83d7 100644
--- a/src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts
+++ b/src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts
@@ -255,7 +255,7 @@ class CellContentProvider implements ITextModelContentProvider {
 		}
 
 		if (result) {
-			const once = result.onWillDispose(() => {
+			const once = Event.any(result.onWillDispose, ref.object.notebook.onWillDispose)(() => {
 				once.dispose();
 				ref.dispose();
 			});