General: Updated design of all pop-up windows.

Check: In the absence of payment conditions, the due date shows ‘Invalid Date’. (RESOLVED)

Check: In the absence of payment conditions, skipping documents does not work. (RESOLVED)

Check: Added validation for the maximum number of characters (25) for an invoice number in SnelStart.

Check: Due date is not recalculated when the invoice date is copied from the PDF. (RESOLVED)

Split: Documents larger than 100 pages are sometimes not split (RESOLVED).