[Vm-dev] What is exactly the problem when evaluating stuff from Workspace and Cog?

Hi. Sorry for my ignorance, but I remember hearing about that evaluating stuff from a workspace may not be the best choice when we want to test stuff on Cog. And in fact, today I suffered that. I put a breakpoint in the method lookup, where the dnu is thrown. And then from a workspace I executed:

TestCase new adasdassad

And didn't stop. Then I put that in a method:

MyClass >> blah TestCase new asdadsadasda

And did MyClass new blah

and the breakpoint stop....So, can someone explain me what black magic happens with the Workspace? is something related to the Compiler evaluation ?

Thanks in advance,