On my part the distance between staves is different on the second page. Is this automatically generated or can I change this?
You can’t manually tweak the staff spacing yet (though that is coming soon) but perhaps you can achieve the results you want by changing the values in the Vertical Spacing page of Layout Options. You don’t really say what the problem is, so I’m guessing what the solution might be.
Sorry for my bad explanation. The part is 2 pages long. On the first page you see a different distance between the staves than on the second page.
OK. The first page is vertically justified, and the second page is not. If you go to the Vertical Spacing page of Layout Options and change the lower threshold for justification from 60% to 50% you will find that the staves on the second page spread out to fill the height of the page.