The Combat Planner is a new feature of Interactive Dungeon that allows you to zoom in a specific section of the map and run a segment by segment, round by round combat.

While the ID map is running, you can now click on one of the two Combat Planner icons
that are located in the top toolbar.

A menu then appears, allowing you to set up the initiative of the players and the foes they will be fighting.

You then place the players on the map...

...and the foes they will fight.

When the combat starts, an arrow will point down on the next combattant in line. The current round and initiative segment is also displayed at the top of the screen.
You can right-click on a combattant's icon and do a number of different things: change his initiative, use the "cast a spell" function to keep track of an event set duration in rounds, view the active events for that combattant, or slay that creature...
Click here to view the combat planner help file.