Why is Icon for item damage+1 item Armor +1 abilities is invisible?

[Map Designer]

item Armor Bonus+1, Item damage Bonus+1?

are there any other invisible abilities?

I tried playing around with item ability-false, and hero ability-false but it is still invisible.

is it something that all item passives share?

I did try with item actives and they are visible.

 

[Shar Dundred]

Some abilities are simply hard-coded to be invisible and cannot be made visible.
Ask Blizzard about the why.

 

[Raydin]

A good deal of item abilities are like that, invisible in the abilities window. If you want an armor bonus ability that's visible try Spiked Shell under neutral hostile, just set the Returned damage factor field to 0.

 

[Chaosium]

Most if not all of the item passives aren't visible. Life/mana regeneration, damage bonus, attribute bonus, movement speed, etc.

You can always add them to your unit and add fake passives based on e.g. True Sight.

 

[Map Designer]

Most if not all of the item passives aren't visible. Life/mana regeneration, damage bonus, attribute bonus, movement speed, etc.

You can always add them to your unit and add fake passives based on e.g. True Sight.

hmm
I see

 

[Raydin]

Most if not all of the item passives aren't visible. Life/mana regeneration, damage bonus, attribute bonus, movement speed, etc.

You can always add them to your unit and add fake passives based on e.g. True Sight.

Exactly this, simply use dummy abilities