Bug 123499

## Steps to reproduce

* open a calc or impress document in lool
* double click on a cell (calc) or a text box (impress)
* change the format of part of the text, for example put some words in bold (click on B in the toolbar)
* don't do anything else : don't click on another cell, and don't type Enter or Esc
* click directly on the closed button (red cross) to close the document

## Actual behaviour

* the document isn't saved : the changes made on the text format are not saved

## Expected behaviour

* the document should have been saved.

## General server configuration

**Operating system:** Linux 3.10.0-693.21.1.el7.x86_64 Centos 
CentOS Linux release 7.4.1708 (Core) 

**Webserver:** Apache/2.4.6 (CentOS)

**Database:** mysql 5.5.56

**PHP version:** 7.2.5
Modules loaded: Core, date, libxml, openssl, pcre, zlib, filter, hash, Reflection, SPL, session, standard, apache2handler, bz2, calendar, ctype, curl, dom, mbstring, fileinfo, ftp, gd, gettext, iconv, intl, json, ldap, exif, mcrypt, mysqlnd, PDO, apcu, posix, shmop, SimpleXML, sockets, sqlite3, sysvmsg, sysvsem, sysvshm, tokenizer, xml, xmlwriter, xsl, mysqli, pdo_mysql, pdo_sqlite, wddx, xmlreader, apc, smbclient, zip, Phar, libsmbclient, Zend OPcache

**LibreOffice Online version:** Collabora Online 3.4.1 or 4.0.0

**Nextcloud version:** 15.0.4

** richdocuments version:**  3.2.1 or 3.1.1