The default form that comes with the PDF solution pack has a couple of issues. Pull requests:
7.x - https://github.com/Islandora/islandora_solution_pack_pdf/pull/93
7.x.1.5 - https://github.com/Islandora/islandora_solution_pack_pdf/pull/95
- typeOfResource is hidden and it contains a default value of text.
- the default value is incorrect as the typeOfResource reflects the original analog or born digital content. eg. a PDF of a map would have a typeOfResource of cartographic.
- turned the field into a select with the typeOfResource terms
- Added label to genre element
- Embedded the subject elements in a tabs/tabpanel form field