Icon of ability is not shown

I made an ability using ability:

Decrease Damage From Magic (Runed Bracers Ability).

I set Learning Icon, Normal Icon and it's X and Y of Hero and when I enter Hero Learning skills, Icon is VISIBLE, but after learning icon is NOT VISIBLE.

How could I fix this problem without Triggers and spare this ability for my hero?

Item abilities can't have icons. So you have two options: trigger the adding/level up of a dummy ability (for the icon/tooltip) whenever the item ability is leveled (or the other way around) or try to find another ability that isn't hidden that does the same thing you want.

Elune's Grace has a "Magic Damage Taken" field but that might be damage from Magic attack type rather than spells.
Can't think of any other abilities off the top of my head.

If I remember correctly, Elune's Grace does also affect spells.

Elune's grace DOES affect spells and you can use SetPlayerabilityAvailable (false) for it to hide icon. Effect will stay. Though this way player wont be able to learn skill

you could use the defend ability and change it into a hero ability. that does have a field for reducing damage fra magic.

There's an easy catch-all solution to this problem;

1. Create a set of Runed Bracers abilities called "Runed Bracers (level 0)", "Runed Bracers (level 1)", "Runed Bracers (level 2)", "Runed Bracers (level 3)" (or however many levels you have, but you need a level 0 too)

2. Set the effects of the levels 1-3 abilities as normal, but make the effect of the level 0 ability nothing.

3. Give the hero the level 0 ability.

4. Create a custom ability based of Tinker's passive, and it's effect appropriately. The passive will replace the original ability (which in our case will be "Runed Bracers (level 0)") with a different ability based on the level of the Tinker's ability, so when you put one point into it it will replace "Runed Bracers (level 0)" with "Runed Bracers (level 1)", etc you get the idea.

IMO this is the best solution for lazy people like me, you can even replace multiple abilities so if you had 2 separate effects like magic damage and plus health, you can do both easily.

I'm not surprised that people steer clear of funky things like tinker, but it can be handy.