Currently, all your forum categories will be available under your default main product (support.mydomain.com). We already have plans to make the generic portal customizable, that is, to choose the required Forum & Solution categories to be displayed on the generic portal. 

On the multiple products setup, you can map one 'Top level forum category' to each product portal (product.mydomain.com) and you can do by following the below steps:

- Go to Admin -> Multiple Products (Under General Settings) -> Edit (on the required product portal)

- On the 'Edit Product' page under 'Portal settings', select the required category from the drop-down list to be mapped to the product portal

Also, we are working on the ability to add multiple forum categories to any product. We will keep you posted once we roll out the features. 

We have rolled out an update that will allow you to select multiple forum categories to a product. 

Go to Admin -> Multiple Products -> Edit (required) Product and you will have the option to select categories under 'Portal settings'

So there is still no way to filter solutions on a product support portal from the default support portal?

Mark, we are currently working on the feature to manage even the default support portal similar to the product portals. You will have the option to choose the required Solutions/Forums categories (similar to product portals) for your default support portal as well. We are expecting the feature to be made available in July. 

As promised, we have rolled out the enhancement for multi product/portal. You can go ahead and choose the required Solution and Forum categories for your main portal (as opposed to the existing option for multiple product's portal). Below are the steps:

- Go to Admin -> Portals 

- Click on your main portal (usually the first in the list)

- Select the required solution and forum categories under Portal Categories

- And hit 'Save'

Hope the enhancement is helpful, do let us know your feedback.