The Tabs extension does not work in a custom block.

Hi,

When added to a custom block, the tabs don't work properly.

They appear in the block settings, but cannot be toggled, and the fields are missing (they are actually there, but hidden with CSS).

Here is a screenshot -> https://prnt.sc/zTfOp8b02LXl

I prepared a test theme (vanilla Underscores) which have a simple Meta Box with tabs, so you can quickly test yourself. I grabbed the metabox code from the docs (https://docs.metabox.io/extensions/meta-box-tabs/#defining-tabs).

Here's the teste theme -> https://dl.dropbox.com/s/myfxeo0uyip140e/test_theme.zip

Thank you.