src/vs/workbench/services/dialogs/browser/abstractFileDialogService.ts/AbstractFileDialogService/showOpenDialogSimplified
class AbstractFileDialogService:	protected async showOpenDialogSimplified(schema: string, options: IOpenDialogOptions): Promise<URI[] | undefined> {
		if (!options.availableFileSystems) {
			options.availableFileSystems = this.addFileSchemaIfNeeded(schema, options.canSelectFolders);
		}

		const uri = await this.pickResource(options);

		return uri ? [uri] : undefined;
	}