Submachine didn't understant what was going on when he entered the Quests submenu. Discussing a little bit, we reached the conclussion that there's a need for a little text on the upper box of this submenu telling where to click and what we're seeing.
Something like 'Click on the left list to see the quest lines and on the FIGHT button to chellenge them!
The red marked quests are the ones you haven't yet completed'