the "play" button is grayed out

I downloaded the new launcher and played with it for 10 days. Today I wanted to play with my friends a minigame on my server (hosted by me) but the "play" button was grayed and I couldn't click it. I tried to restart my PC and it didn't help. I have java 7 updtae 25 64bit and the launcher worked fine with it untill now. EDIT: you can press the ENTER button on the keyboard and it'll work. but the "play" is still broken