Answer:
You see a boat filled with people. It has not sunk but when you look again you don't see a single person on the boat. Why?
You cannot keep me until you have given me. What am I?
You throw me out when you use me and take me in when you are done.
My second is performed by my first. A thief by the marks of my whole might be caught. What am I?
What can you catch but not throw?
I am used for light yet I am solid. Without me you would feel enclosed. I hate being touched especially with a lot of force. I like to be in buildings.