Ability to manual add Boards to Portfolio Dashboard

Description

We would like to have the ability to manually select (extra) Boards to be added to the data of a Portfolio Dashboard, that have automatic linked Boards.
Which currently is not possible as the button is greyed out (see screenshot: Upload and share screenshots and images - print screen online | Snipboard.io)

What are you trying to achieve

Manually adding Boards to Portfolio Dashboards which are automatically added when Board created.