UPDATE: This turned out to be a bug in R14 of the SDK tools. It has been fixed in R15 which was released on Oct/27/2013. Updating to the latest release solves
That's not what happens to me. If I scroll up it won't scroll down automatically when new lines come to the logcat until I scroll it to the bottom.
Maybe it's because of the Eclipse or the Android SDK version. I'm using the latest right now.