In v2 of shipstation, we were able to click on package dropdown box and then scan a barcode on the outside of the box in order to select the custom package.
I was hoping that you may provide us a bit more detail about this workflow.
A few questions we had: Are you using a preset? Precisely which barcode are you scanning? To us it sounds like you are clicking the package dropdown and then scanning a preset hotkey barcode, and we shouldn't need to click into the dropdown to do so. A more detailed breakdown of this workflow may help us understand the behavior you are running into.