In both the "new and old" admin solution, it is impossible to know which of the line items you are viewing if you don't keep track of this yourself somehow.
Example: If a customer orders 10 t-shirts – I load up the first design, and download the files I need. Then I click the button for the next product, but at some point I lose track of which product I am looking at, because all the buttons are the same color and with the same text (Product name).
Please include the line item number somewhere, and add a class to the active button in the external admin solution (see screenshot).
Also, perhaps also move the elements panel (bottom) up above the product viewer, as it can take up so much of the screen and pushing the relevant content far down. We do not always need to see all the design, just need the download settings/buttons available.
Thanks, good to see this implemented. Although only in the new external admin solution, which we won't be using. In regular WooCommerce this could be fixed by just displaying the WC Line Item Number in the product details and append the same number to the header of the Order Viewer box when loading a product.