Dear mandelkind,
Thanks for reporting that bug, Meta Box plugin itself updated the code and post_type now becomes property of field instead of field.query_args. So you'll have to define field like so:
'type' => 'post',
'name' => 'Page Dropdown',
'id' => 'page',
// note that
'post_type' => 'page'
// instead of
'query_args' => [
'post_type' => 'page'
]
We'll release an update for Meta Box Builder, currently, in this version, you can do it by using Custom Attribute, like this example:
http://prnt.sc/agankf
.
