In Hydrator UI, we show all the macro keys and the user has to enter those values or delete those entries in order to run.
Ideally we need to populate those values if we are able to resolve in preferences. Currently even if user know those values will be resolved by preferences, he has to delete those entries in order to run the pipeline, which is tedious for repeated runs where preference doesn't change.
It will be more robust if we can populate the values for macro keys from preferences and user can override them if desired.
Also this allows to easily disallow the run if the macros for required fields in plugins are not provided.
Added feature where values of macro arguments are automatically populated and shown in the UI when running a pipeline, if those values exist as Preferences.
Moving to 4.2