It could pre-populate with your “default” input but, there should be a “Input Routing” field with a dropdown in the “Add Audio Track” dialog box to choose a different one.
At present it does Default to input 1 of your harware as far as I’m aware. But a lot of the time you know what input you want use as your creating a track. Doesnt make sense to me not to have it on the dialog. Its a further step I have to do after closing it almost always.
Actually at present it uses the input that you designate as “Default”. I mentioned it so that, if they ever added a field to the dialog, that it too would pre-populate to whatever was chosen as default, then have a dropdown available to choose any other.