In 1.3 and previous, you can rapidly add lines by entering a part number, qty, etc in a blank box and hit enter which essentially submits the form with the first submit button. In 1.3 and earlier, this is the "update" button, which reloads the form, and iirc, puts cursor in the first available part number.
Now in 1.4 (and possibly recent 1.3) hitting enter actually submits the "x" button next to the part number, deleting a line item. This is a big usability regression...
Which browser/OS?
(I am not able to reproduce this on Chrome/Linux)
Hmm, this was on chromium/linux -- have you tried adding multiple parts to the invoice?
Yeah. I did. No issues. Are there any js errors in the console?
Ok, so I am considering duplicating the button row and putting it at the top of the form too.
My reasoning is that this is likely to be the most robust solution since it will ensure that there is a button before the [X] buttons.
6867 should be a robust fix that doesn't depend on javascript.