Collapsible Depends On: Set based on empty/null value?

[oguruma]

I’m trying to set a section break to be collapsible based on whether a Text field is empty, but no expression I have tried seems to work…

What’s the proper way to set a section as collapsible if a certain field is empty?

[NCP]

Please check the default example.

[oguruma]

Right, but the problem is that I need to set the field collapsible if the field is empty…