Actually, I saw the symbol of repairing appearing, so that's why I put items on the ground. But now I know why it didn't work...

another questions about configurations:

How do you set some more configurations, except for the configtool.exe file? such as, changing mousebutton settings, key settings, exit game settings. Is there some sort of .cfg file or anything?
Also, how do I find a list of all keys that are being used in the game? For example, the ALT-key is not in the key config list, but it can be used in the game