Interesting, i hope its not something else on my device interferring.

For me I did this:

Sort A-Z off, Checked to bottom off, Auto rotate off, landscape or portrait doesnt matter

- Opened your app (there was nothing in the list)
- I added a few items (actually 6)
- Clicked save (them items now appear with the checkboxes)
- Tapped menu and clicked sort A-Z (No items in the list now!)

Im now at the point where I have no list.

If I click edit list at that point, my items are still there, if i then click save the list displays as normal with the sort A-Z still on.

If im at the no list point and click sort A-Z again to turn it off, it does turn off but there is still no list.

If im at the no list point and click checked to bottom, it turns checked to bottom on and my list reappears.

Maybe its just me? Im not due to flash yet so I cant try it out with a fresh device.

I'll try an uninstall and re-install along with rebooting at the end and see....