Description

When adding and editing the Accordion widget, the content disappears and it's not retrievable.

Related to: #2324

Steps to reproduce

1. Fresh install of WordPress 4.8.2
2. Fresh install of Elementor 1.7.4
3. Activate Twenty Seventeen Theme
4. Edit Sample Page with Elementor
5. Drag Accordion Widget onto screen.
6. Start adding content to content area, adjusting sort order of accordions while editing and expanding / contracting boxes. Just play around with it.

It's intermittent but there is something going on for sure. I took a video: https://cl.ly/1X0M1d2B2A1F

I also didn't see any javascript errors in the console.

Environment

== Server Environment ==
Operating System: Darwin
Software: Apache/2.4.23 (Unix) PHP/5.6.28 LibreSSL/2.2.7
MySQL version: 5.7.16
PHP Version: 5.6.28
PHP Max Input Vars: 1000
PHP Max Post Size: 8M
GD Installed: Yes
Elementor Library: Connected

== WordPress Environment ==
Version: 4.8.2
Site URL: http://local/elementor
Home URL: http://local/elementor
WP Multisite: No
Max Upload Size: 8 MB
Memory limit: 40M
Permalink Structure: /%postname%/
Language: en-US
Timezone: 0
Debug Mode: Active

== Theme ==
Name: Twenty Seventeen
Version: 1.3
Author: the WordPress team
Child Theme: No

== User ==
Role: administrator
WP Profile lang: en_US
User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36

== Active Plugins ==
Elementor
Version: 1.7.4
Author: Elementor.com

== Debug ==
Errors: There are no errors to display