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
I also think it is "more aggressive" since the latest update! And it actually stops auto-scrolling when I scroll 10 or more lines up.
The best solution I have is clicking in the line you are interested in. If the logcat scrolls down too far and you don't see your line any more just press ArrowUp or ArrowDown to jump back to the line you were looking at.
Window => Preferences => Android => Logcat
Uncheck the box called:
Display logcat view when there are messages from
an application into the workspace
If you write pid:pidofyourapp (which is written under online column in Device tab) in the search box,it will show the logs you wrote in your application.
update to the latest version. the new logcat automatically filters your logs into the app-specific crash logs when you build-launch your app via eclipse.
If you're only debugging crashes, click on the red (E) (error) filter for your main logcat, and keep your filter tab set to default to view all lines that are being reported by your application.
What ends up happening, when your application crashes it stays closed unless requested to restart by your choosing. So, the last lines in the logcat will be the crash report. This is one of the ways of how I debug crashes.
In the LogCat tab on the upper far right there is a down pointing arrow with a line under it to enable
"Scroll Lock"
On older versions it's a pause button to
"Pause receiving new logcat messages"
That should do the trick!