Widget Groovy controller - Class Not Found Exception

[JdidouBrahim]

When creating a groovy controller for my widget,i always get a "Class not found exception" which seems logical since the groovy file is not compiled.

Is it possible to define a groovy controller for your widget ? if yes then are there some additional steps to do other then what is mentioned in the Wiki ?
cc @mpern

Thanks in advance,
Brahim