.) Create a class change the class declaration to something like this: 

    public class Test extends NewInterface ;.{

-> An error annotation appears with 3 errors, where each error is sepperated by an empty line.

I think this  
1) just takes to much space in the popup.
2) is (for beginners) still not very clear that we are actually dealing three different errors. 

Why not saying something like:
 +-----
 | Multiple errors found:
 | - '{' expected
 | - illegal start of type
 | - no interface expected here