check viewtype, is string, not interactive

Author: amunger

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

@@ -613,7 +613,10 @@ class SimpleNotebookWorkingCopyEditorHandler extends Disposable implements IWork
 		await this._extensionService.whenInstalledExtensionsRegistered();
 
 		this._register(this._workingCopyEditorService.registerHandler({
-			handles: workingCopy => typeof this._getViewType(workingCopy) && workingCopy.resource.scheme !== Schemas.vscodeInteractive,
+			handles: workingCopy => {
+				const viewType = this._getViewType(workingCopy);
+				return typeof viewType === 'string' && viewType !== 'interactive';
+			},
 			isOpen: (workingCopy, editor) => editor instanceof NotebookEditorInput && editor.viewType === this._getViewType(workingCopy) && isEqual(workingCopy.resource, editor.resource),
 			createEditor: workingCopy => NotebookEditorInput.create(this._instantiationService, workingCopy.resource, this._getViewType(workingCopy)!)
 		}));