I followed a hero abilities tutorial and that learn button I had to create seems to be crap.
a) It is ALWAYS displayed, even when you have no points to spend - how to disable that?
b) It shows even when you select enemy units (on them)! - again, how to disable that?
Please don't tell me those are hardcoded -.-"
I'm not sure about requiring ownership of the unit to see the button, but it's very possible to hide the button when there's no points to spend. Create validators/behaviors for each hero level so that you can run a Requirement (Show) check on total abilities learned vs the level of the hero. So, if your hero has put 3 points into Ability A and 4 points into Ability B and is level 7, it'll hide the button. But once he becomes level 8 it'll show the button again until you level another ability.