When inputting a transaction, if the user inputs a number greater than four digits (not including the decimal) and advances to the next field, GnuCash will autoformat the number to the preset formatting. If you make a typing error and go back and delete one of the digits changing the total number of digits/numerals, the amount will change into an invalidly formatted amount and create an error message.

For instance, I accidentally typed "15000" when I meant to type "1500". I didn't catch the mistake immediately, pressed the "tab" key to advance to the next field, and GnuCash automatically formatted the amount to "15,000.00". Upon realizing my error, I used the mouse to position the cursor at one of the extra zeros thinking I could delete it, fixing the amount, and move on. Instead, the program issued an error message. ("An error occurred while processing 15,00.00.") I had to also delete the comma formatting creating the basic "1500" number again.

I understand the error appears to be from the number now being formatted incorrectly, but it seems as if the program should be "smarter" than that. In a spreadsheet, the number is separate from the formatting. I can change an existing number and the software will reformat it displaying it correctly. I was surprised that GnuCash didn't do that. Maybe it's something not easily changed, but I wanted to bring it to the attention of the developers.