After applying patches for bugs 6446 and 6543 to fix the "Batch item modification" from freezing when trying to save, there is still an issue, albeit minor. When deselecting all items for batch editing, and then saving, the progress bar changes to NaN% and nothing happens. The code should recognize that the user is attempting to save 0 items and complain about such, rather than just freeze.
Bug 6446 and But 6543 referenced above are both closed and I cannot reproduce this problem in master.