Found a repeatable bug.

1. Within the deck module, select a card.
2. Click on one of the column headings to sort the deck by that column.
3. Without selecting a new card, try to add, subtract, move up/down, etc. the card that is currently selected.
4. MA crashes.

Note that after you sort, the card that was previously selected remains the same in the picture and card text modules. However, the deck module continues to highlight whatever card is in the same position as that card was before the sort. E.g. if you select the third card from the top, then the third card from the top will remain highlighted after the sort, regardless of what card is there now. Could be relevant to the crash.