Turn your phone 90 degrees to the left,Background icons flashes when press on the side of the video

[quandan]

current build number: 73
device name: arale
channel: ubuntu-touch/rc-proposed/meizu.en
last update: 2015-07-30 06:06:02
version version: 73
version ubuntu: 20150730
version device: 20150709-8965e37
version custom: 20150716-819-8-42

Steps:
1.There is some video in your phone storage
2.Open the galley app in app scope
3.Choose a picture or a video ,just one press on it
4.Turn your phone 90 degrees to the left
5.Press the blank black space several times and keep your eye on the top of the screen, focus on the flickering between the indicator and the white options bar

Expectation:
There will be normal to open a file in gallery

Actual result:
when acting the 5th step, there are some app icons flicker between the indicator and the white options bar . it's like the part of background icon just come out