Support › Meta Box Builder › Override
The metabox builder overrides any PHP based versions of the metaboxes. Is it the intended workflow to build in the builder, copy the PHP to a theme/plugin, and then disable the builder?
The Builder uses the Meta Box filter to register meta boxes, see:
You don't need to copy code to another place and then disable the builder, feel free to use it as the way you want.
I have written this also on github: when I disable the metabox builder I get an error message referencing Line 48 in core.php -- which means I can only use metabox with the builder, but not without.
Maybe a php 7 issue?
Nevermind the error: I have found the mistake: I was registering a filter that didn't work.
Now I am all set: I can use mapbox as I like it!