Can there be a Timeline bar where the DM can enter the time passed since a fixed event.
Example: the characters enter a dungeon, they cast a bunch of enhancement spells on themselves which last 1 hour. As they explore the dungeon the DM can have a countdown bar at the top of the screen showing Time passed since the dungeon was entered. The DM would manually advance the timeline. This way the players have an idea of how much time until their spells expire.
The timeline can have an option to put in new markers so the players can add future flags showing when their spells expire. As the DM advances the timeline he put a special marker on the timeline showing the advancement.