I got some delay for the assembling interface because I working on the display of the requirements.
In clear if the player select an infrastructure, in the available list, and this one cannot be assembled or build due to its requirements, a text will be displayed explaining which requirements aren't fulfilled.
Nothing thrilling but since FARC isn't simple, even at this stage, the more information I can provide to the player, the better it will be.
It's a bit like what I did for the enforcement of policies, and their requirements.
This code for this is unified and will work for the two modes (assembling / building).