bulding and reforcecement few questions

[Circuit]

So i try to buy a pd on a planet. So i open the menu of the building reforcement. I see no ''buy button'' so i try to double click to purchase a pd. I try it with the check makr available on and off. Maybe i did something wrong.

Before my humiliate death, i try to make unit reforcement. To be honest i try few thing to understand how it work. But when i cancel, i get no refund. It is on purpose??

[Ze_PilOt]

Drag & Drop on the planet.