ionicLoading showBackdrop error in v1.0.0-beta.11

Hello everybody!
I’m doing an application using ionicframework.
I have some problem with ionicLoading.
This is my code

$scope.loading = ${
	template: 'Update successful!',
	animation: 'fade-in',
	showBackdrop: false,
	maxWidth: 200,
	showDelay: 0

In previous version, it’s good. But in new version, i set showBackdrop: false
when ionicLoading show,although backdrop not show, but i cannot click back button until it hide.
Please help me!
Many thanks.