ability dependant on another ability activated?

is it possible to have a greyed-out (faded out) ability that a hero has that stays unused until another ability is activated.. and then while that ability is running, the greyed-out ability can then be cast until the other ability stops?

like say if a mountain king has an ability called "slam" but it wont let him use this ability unless he has avatar activated.. and he can cast it as many times as he wants til avatar runs out.

any ideas if this is possible?

My guess is you make a custom unit that has no model, doesn't block other units, and is invunerable. Name the unit the same name as the ability that needs to be activated (or whatever you wanna call the requirement), then in the ability that you want to be greyed out, set the requirement to the custom unit, and set "Check Dependencies" to True.

Then create a trigger that fires when the unit starts casting the requirement ability. Make it so that it will create the custom unit (anywhere appropriate is fine), wait for the amount of time that the spell is active, then remove the custom unit.

What should happen is (using your mountain king example again) when Avatar is used, the custom unit is created, which mean you have all ther requirements needed to cast Slam, allowing you to cast it. Then when the time runs out, the custom unit is removed from the game, and since you no longer have the requirements to cast the spell, it is disabled.

BTW, this is 100% theory, and I haven't used it at all. :)

Theory yes, but it's a good one. That's pretty much how the NOD MKII works in battleship command, with having to purchase a reload after each use.

I have used it, it works.