Spellcaster option not appearing in the tweaks tab?

[Darkcell28]

The description for the system says that there should be an option to open the spellcasting tab on the tweaks screen for characters, but there isn't one. Am I looking in the wrong place?

[SobranDM]

I changed the system but it's a bit unintuitive. I need to switch it to support both methods. In short:

Drag an Art and/or Spell onto the sheet and the appropriate section will appear.