Be able to choose from users across idea portals when changing the idea creator

This surfaced as being useful when a user manually added an idea for someone that they received via email and wanted to change who the idea was created by. When they went to change this, they were confused as to the available set of portal users they could choose from. They had two different private portals, both of which included the same set of products, that each had a separate set of users. Since the idea was added to a product and the product belonged to two different portals, the assumption was that the "Change idea creator" dialog window would include users set up in both portals.

As it turns out, only a single set of users from one of the portals was displayed as an option.

This is because users belong to portals and not to products and users in one portal are not available in another portal to be set up as the creator of an idea. The logic for how it is determined what portal an Idea is submitted in, and, subsequently which set of users are available as Idea creators is as follows:
1. If the idea was submitted via an idea portal, then the list of users available are the ones in that idea portal.
2. If the idea was created directly in Aha!, then Aha! tries to find the best matching portal. The current logic for this:
a. By taking the first public portal, and if there are no public portals then
b. Taking the first private portal

There are a number of ways to approach making this more transparent. Rather than proposing a solution, the desired outcome is to make it easier to choose from portal users from across portals for the same product when you need to change the idea creator.