For as many active and passive icons you have, you have to have same amount of their disabled counterparts.
Take for example the icon of the Critical Strike ability.
This one uses active version BTNCriticalStrike for when you want to learn it or skill up as a hero, and PASBTNCriticalStrike for the learned version.
Now you use 2 icons and each needs its disabled counterpart.
So the active version, used for when you want to level up your spell, uses DISBTNCriticalStriker and the passive version (PASBNTCriticalStrike) uses DISPASBNTCriticalStrike.
So in total, the critical strike uses 4 icons -> 1 "active" version, 1 "passive" version and 1 disabled icon for the passive icon and 1 disabled version of the active icon.