Can scroll content behind the overlay menu in iOS Safari

[ionitron-bot]

Original issue by @longgt on 2017-10-30T11:08:11Z

Ionic version: (check one with "x")
(For Ionic 1.x issues, please use https://github.com/ionic-team/ionic-v1)
[ ] 2.x
[x] 3.x
[ ] 4.x

I'm submitting a ... (check one with "x")
[x] bug report
[ ] feature request

Current behavior:
Can scroll content behind the overlay menu in iOS Safari.

Expected behavior:
Can't scroll when the overlay menu is opened.

Steps to reproduce:

1. Show List page in Safari
2. Toggle Menu button
   After menu is showed, the content behind backdrop can scroll.

Related code:

The same issue is marked as resolved and closed but still reproduce on the latest version.
ionic-team/ionic-framework#6656

A sample application via GitHub

https://github.com/longgt/ionic-virtual-scroll-demo

Ionic info:

cli packages

    @ionic/cli-utils  : 1.9.2
    ionic (Ionic CLI) : 3.9.2

local packages:

    @ionic/app-scripts : 3.0.0
    Ionic Framework    : ionic-angular 3.8.0

System:

    Node : v8.5.0
    npm  : 5.5.1
    OS   : Windows 7