We have indeed redesigned the Invoke Workflow a bit so that we can use 1 version for both Windows and Cross-Platform projects.
It automatically loads the arguments without even having to click the Import Button whenever you select your XAML file:
You only ever need the import argument button to fix things, in case there is a mismatch in the configuration of the Invoke Workflow File <> the XAML file.
The power of habit is strong though, which I totally understand and overlooked on the first iteration of the new design. This is why we will make a further adjustment to how the activity looks like in the very next patch to System activities:
The idea is to reduce the emphasis on the buttons a bit to reduce the confusion: