When merging (and deleting) categories, 'Budgeted' values are deleted (and it mentions this with a warning), but there's no indication as to what happens to manually set balances in the 'Available' column.

For example, if you create a 'balance adjustment' to track existing funds in Category A, and you merge Category A with another one (Category B), it should either add the funds from Category A to the current Available amount of Category B, OR indicate that 'Available' amounts of Category A will be deleted (and that the user should manually make that transfer before moving forward with the merge and delete).

Note: Since transactions are merged into the second category, deleted categories with 'Budgeted' values would create an imbalance in all historical periods. Ideally, both 'Budgeted' and 'Available' values should be added to the existing values in the remaining category that you merge to.

Otherwise, perhaps "merge & delete" should be disabled for categories with budgets in the meantime. Users would need to clear out all budgeted values for the category before they can "merge & delete".