"Insert More Tag" button disappears

Hello,
the “Insert More Tag” button is intentionally disabled by Black Studio TinyMCE Widget to prevent its use in widgets, as they do not need it. Normally this only affects editor instances inside the widgets management screen, but if you are using it in conjunction with Page Builder, which offers the ability to put widgets inside post/page content, it also applies to editor instances in the post edit screens.
It wouldn’t be a problem to re-enable it in this case (will do in next release), but after a quick test, I found out that the More tag, when put inside a widget inserted through Page Builder, is simply ignored. I think this could depend on the way Page Builder generate the post content / excerpt. I noticed this also happens if you disable Black Studio TinyMCE Widget completely and try to put the More tag in native text widgets inside a post. I think for this, it’s better to ask Greg, the author of Page Builder.

Please check the new version 1.3.0 just released, which has support for the “More tag” button, when using it in conjunction with Page Builder.
So now it is possible to insert the tag inside the editor, but unfortunately it looks like it’s not correctly rendered by Page Builder. I would suggest to post to their support forum.