There is the green lab tiles that say, when you buy them you do the ability once when you buy the tile, then no more. But does that mean I lose the green ability if I cover it up? The way it is worded sounds like I just activate it once and get the benefit, but don't lose it if I cover it up.
Here is a relevant post from the FAQ:
Q: I don't understand lab upgrades with green text. Do they only trigger one time after purchase and then will be ignored for the rest of the game?
A: (From designers) The green text on certain lab tiles give a passive ability - it cannot be activated by placing a worker on it. The tile Groundskeeper shack has the green text "Increase your security level by 1 at no cost." - You do this once only, when you buy the tile. During the lab phase, you may activate its second ability "treat your security level as +1 for this round" by placing a worker on it.
The Break Room allows you to hire 1 additional specialist in the game. Other players will be able to hire 3, you may hire 4. (or 5 if you buy two Break Rooms)