Hmm, where?

Sorry, but in the single edit metadata I have in the 'Change cover' group:
- Browse
- Remove
- Crop
- Download cover
- Generate cover
(I've translated these to english, so it may be not 100% exact)
What I think is:
Browse - browse for image file
Generate cover - will generate it using metadata, but not taking the first page
Download - will look in external sites
So where is located the option for taking the cover from the first page of the PDF file?