When im trying to make a screenshot with the standard screenshot utility on elementary OS (Version: 0.2.1 "Luna" ( 32-bit )) the window flashes and the picture saved is just my desktop background (or the area I grabbed) and not the window I wanted to screenshot. I already tried rebooting etc. Any ideas?
This community is the wrong place for reporting issues, sorry. If you want to report an issue with the developers, you can do that as described in How can I report an issue with elementary OS to the developers?
Unfortunately, elementary OS Luna is not actively developed anymore. While the operating system is still secure (as the Ubuntu base still delivers security updates), there are very few elementary OS developers still working on delivering bug fixes and updates for elementary OS software on Luna. Therefore, reporting this issue will most likely not result in any fix.