Still getting used to the game and, got my first character at lv 30 recently and saw that I missplaced 2 points in the skill tree. The thing is, I would suggest to add a [ + / - ] visually to add or retrieve points on each skill, and a button [ F ] default to commit those points. Just to save you some, "oh I miss-placed this" situation.
Also, depending on the "upgrade" , the icons could be different colors as well: like: red for new abilities, blue for "minor I, Exploration Disciplne etc.." unlock ... Plus a description of the "unlocked" power.
Something like this? (I edited a little b