This is one of the few times I have to use the mouse in IDEA.
When a JUnit test fails I want to read the failure message, but the stack trace is usually long enough that the message scrolls out of view. Also, the lines near the top of the stack are the ones that are usually most interesting to me.
A simple solution would be to scroll the console back to the top when the test is done but the message is important enough that perhaps it should have it own screen real estate or perhaps appear in a tooltip when you mouse over the failure icon in the JUnit tree view.