Steps to reproduce the issue

Menus -> Main menu -> New -> Select (Menu type item) -> Contacts -> Single contact -> Create

Expected result

To save of save &close the contact item

Actual result

It is not possible to save or save&close the contact item

System information (as much as possible)

Joomla_4.0.0-alpha7-dev-Development-Update_Package.zip
These packages were built based on commit 0d68d9e
These packages were last built: Monday, 31 December 2018 03:00:41 UTC
PHP Built On Darwin iFred-iMac.local 18.2.0 Darwin Kernel Version 18.2.0: Mon Nov 12 20:24:46 PST 2018; root:xnu-4903.231.4~2/RELEASE_X86_64 x86_64
Database Type mysql
Database Version 5.6.35
Database Collation utf8_bin
Database Connection Collation utf8_general_ci
PHP Version 7.1.8
Web Server Apache/2.2.32 (Unix) mod_wsgi/3.5 Python/2.7.13 PHP/7.1.8 mod_ssl/2.2.32 OpenSSL/1.0.2j DAV/2 mod_fastcgi/2.4.6 mod_perl/2.0.9 Perl/v5.24.0
WebServer to PHP Interface apache2handler
User Agent Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:64.0) Gecko/20100101 Firefox/64.0

Additional comments