Below we will explain each column of the Port Forwarding tab:
Port Forwarding rules are loaded from top to bottom, so the rules at the top of the table have priority over those below (being possible until they overlap the settings of the low rules).
In the Allowed and Blocked columns it is possible to view more details by hovering over the address objects, a list with all the IPs that are part of the object will be displayed, an example follows:
In addition, by clicking on the  button displayed in this window, it is possible to edit the address object, as shown below:
When too much data is entered, exceeding the limit of the table cells and / or in the object details window (mentioned above), scroll bars will appear to facilitate navigation.
For more information on port forwarding, visit this page.