sbt crashes often when run inside the elt shell

[GoogleCodeExporter]

What steps will reproduce the problem?
1. run sbt within the shell
2. Try to scroll history more than once using ArrowUp key or to use Delete key

What is the expected output? What do you see instead?
For BackSpace: Type a character, and try to delete it
For ArrowUp: scroll through sbt's history

Instead sbt crashes with 'java.lang.ArithmeticException: / by zero'

What version of the product are you using? On what operating system?
elt   Terminal  1.1.2.201208131620  com.google.eclipse.elt.feature.group    Google, 
Inc. 

On a MacOS.

Please provide any additional information below.

Eclipse-Juno

Original issue reported on code.google.com by koolmokpox on 5 May 2013 at 3:52