Building not showing up at build tab

[PiPo]

I tried to add the Lurker's Den to building but isn't showing up at buildingsand advanced buildings.
Only thing i did was adding it to the list of buildings at the Drone's morph ability..

 

[gT.ReD]

did you also add ability buttons on the command card?

 

[PiPo]

did you also add ability buttons on the command card?

You made me realise that you had to look at the other command cards ..
I just need to learn those basic things.
Thanks. (+rep)