destory notebook document only when the editor input is destoried.

src/vs/workbench/contrib/notebook/browser/notebookEditor.ts

@@ -243,13 +243,6 @@ export class NotebookEditor extends BaseEditor implements INotebookEditor {
 		}
 
 		this.list?.splice(0, this.list?.length);
-
-		if (this.notebookViewModel && !this.notebookViewModel.isDirty()) {
-			this.notebookService.destoryNotebookDocument(this.notebookViewModel.viewType!, this.notebookViewModel!.notebookDocument);
-			this.notebookViewModel.dispose();
-			this.notebookViewModel = undefined;
-		}
-
 		super.onHide();
 	}
 

src/vs/workbench/contrib/notebook/browser/notebookEditorInput.ts

@@ -149,4 +149,12 @@ export class NotebookEditorInput extends EditorInput {
 		}
 		return false;
 	}
+
+	dispose() {
+		if (this.textModel) {
+			this.notebookService.destoryNotebookDocument(this.textModel!.notebook.viewType, this.textModel!.notebook);
+		}
+
+		super.dispose();
+	}
 }