Feature Request: Allow Dashboard Extensions to add custom fields for list queries

[taxilian]

Currently, the Dashboard's addCustomFields function uses an includeCustomFields whitelist based on visible columns. This prevents plugins from adding custom field data via extendListDocument.

Use Case:

Our plugin adds a notes cell component that displays icons for customer notes, fulfillment notes, delivery instructions, and order history notes; they change color if there is anything to see for that icon and in the case of fulfillment notes and order history notes we can click to add or edit notes. This is incredibly helpful when fulfilling orders so we can record information from the orders list if there are things we need to remember.

Our implementation (which otherwise works great) overrides the column for the customerNotes custom field; it'd be great if we could register a new column type, but this works adequately almost. The trouble is that when we try to add the extra data using extendListDocument it ignores it because they are custom fields and anything we put in is ignored in favor of whatever we included.

We can work around it by simply adding the other columns and showing them last, but it's a very hacky thing to do and kinda ugly =] It would be better if there was a way we could just force it to add those columns.