Disease Cloud not useable in Ethereal Form?

[Minox]

I'm trying to make a hero that is in ethereal form but he has a Disease Cloud type ability so he can damage units by going through them, however, when he is in ethereal form, Disease Cloud is grayed out and doesn't work, but when I remove the ability Ethereal Form from him, DC does work.

How come DC doesn't work in ethereal, when auras, immolation and other passives do work? Is there a way to fix this or bypass it? And could someone tell me what causes this, and if there are other passive skills that don't work in ethereal form?

 

[busterkomo]

Permanent immolation should work.

 

[Super-Sheep]

Permanent immolation should work.

Immolation doesn't make nearby units to take damage over time, when unit with Immolation moves away.

So it won't work like the Disease.

 

[Minox]

Permanent immolation should work.

Yeah, I know, but as Super-Sheep said it isn't like Disease Cloud, and I want the buff to be applied to nearby enemies so I can make use of it in triggers. Also, I noticed that if I kill the hero, Disease Cloud will work after he is revived, even though the icon is grayed out. That's a bit weird imo

I also noted that if u banish an Abomination, disease cloud and Cannibalize doesn't work for him while he is banished. Same thing for Peon, all his skills are grayed out. Could it be that only abilities that cost mana are useable while banished/ethereal? And a lot of passives still work, but not Disease Cloud, and that bothers me...

EDIT: I just figured I could use Phoenix Fire, however that ability doesn't have an icon and no special effect on the "caster", and I want the cloud effect to be visible on the hero. Could do it with triggers but I'm not sure