[Snard]

Now I have tested it on another device, medion lifetab.
Same thing-switching from horizontal to vertical after starting the setlist results in wrong zoom.

I have reproduced this behavior on my tablet, running the latest MobileSheets (4.0.10). I had actually observed this once before, but had been unable to reproduce it until now.

To make this happen, do the following:

1. Make sure your tablet isn't in rotation lock mode
   
2. Starting with the tablet in landscape orientation, open a setlist that has at least one PDF song in it.
   
3. Load the PDF song. It will appear as expected (the top half of the page displaying)
   
4. Now rotate the tablet to portrait. The song will be zoomed in too far (i.e. at the same scale as was being displayed in landscape)
   
5. If you now change pages in the song, or go back to the setlist and review the song (while remaining in portrait), the display will be corrected.
   

There are actually two separate anomalies; the one I described above is if you have "Display Half Page in Landscape" set in Options. If you don't have it set, you get a slightly different behavior when you rotate the tablet to portrait: the page will remain tiny!

Note that this only appears to happen with PDF songs, not image files.