## Steps to reproduce
* open a text document
* menu Format > Bullets and numbering
* select the Customize tab
* select Bullet in the Number list
* click on the Select... Character button
* select a character
* click on Insert or Cancel

## Actual behaviour

* the Special Characters dialog box is not closed

Workaround : the dialog box can be closed with the cross on the top right of the box

## Expected behaviour

* The Special Characters dialog box should be closed when clicking on Insert or Cancel


## 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 3.2.2

**Nextcloud version:** 13.0.4

** richdocuments version:**  2.0.9