ToME: the Tales of Maj'Eyal

Alright, bear with me here: my Skellie Archer had one point of heightened senses from an escort, otherwise he had not invested in the Survival tree at all. Later, I unlocked the Combat Techniques trees with the intent of checking whether the precise strikes bonus scaled enough to make it worth it (it did not). Then I took those Class points out. Now, without removing the Category point from the CT tree, I put one Generics point in Trap Handling in the Survival tree to check the scaling on that. Then I removed that point. Then I tried to remove the Cat point from CT.The result boggled my tiny brain: