Hi Sascha,
Thank you for waiting and for sharing the login details.
1). The values that we add for the "Not selected" and the "Selected" option in a checkbox field's settings ( hidden link ) are returned when that field's value is called.
When that field is viewed in the admin area's edit screen or in a front-end Form, its label is generated from the value added in the field's "Field name" option.
It was like this even before the latest improvements in the front-end forms editor.
Note: if you'd like the custom values to be visible in the form, perhaps it would be better to replace the "Checkbox" type field, with a "Select" type field.
2). The option "Set checked by default (on new post)?" is only applied when a new post is added, through either the back-end post edit screen or through the front-end form.
The "Shop . Premium" form that is shown in your screenshot ( hidden link ) is for editing an existing post and not for adding a new one.
3). This is also something, that hasn't changed with the latest visual form builder. The conditional check that is added in a custom field's settings only applies to the field's markup and not for the field's wrapping div and the label tags.
To properly hide/show a front-end form field, it should be wrapped inside a "Conditional group", as explained at:
https://toolset.com/documentation/user-guides/conditional-display-for-form-inputs/
4). I was able to reproduce this issue on my test website.
Appreciate you brought this forward and I've passed this on to the concerned team. I'll keep you updated with the progress through this ticket.
For future reference, please note that as per our support policy ( https://toolset.com/toolset-support-policy/ ), only one question or issue can be addressed through a single ticket.
You're welcome to open a new ticket for each new question or concern.
regards,
Waqar