We've discovered a couple of minor bugs when putting an invoice "on
1. Clicking the "On Hold" button from a sales order produces a 500 - Internal Server Error.
But, it works on a sales invoice.
2. After a sales invoice is put on hold, the button still says "On Hold". Through experimentation, turns out that the button seems to be meant as a toggle: clicking it a second time takes the invoice OFF hold. Therefore, when status is "on hold", the button should instead say "Off Hold" or similar.