deleting or moving cardsets from one list to another causes problems on some cardsets due cards number
I had cardsets like this : (cardset1 : 10 due) , (cardset2 : 15) , (cardset3 : 1).
after deleting cardset2, I got (cardset1 : 10) , (cardset3: "0").
the learn button number shows the right value but per cardset due have some problems. after changing the priority the "1" due card is back.
Update: the reason is priorities are not updated correctly. for example if we have 3 cardsets (0, 1, 2) and delete the cardset with priority 1 we should have (0, 1) but now we have (0, 2) which causes this error.
Issue is closed for Release beta 1.