If the field is greyed out, it means that we already support it.
You can hover over the information symbol on the metric or dimension and you'll be informed on what you need to do or why we're not importing it currently:
In order to bring the relevant field into Funnel, you would either need to edit the configuration of an existing source in the actions menu (providing the existing source is reconfigurable):
Alternatively, you can connect a new data source with the relevant configuration selected.
For more information about reconfiguring data sources navigate here. If you want to learn more about the option of having one source with two different configurations please refer to this article.
Search our Knowledge Base for specific information on what data can be retrieved from each data source type.