This paper discusses the prototyping of programming environments
for object-oriented concurrent programming languages.
We advocate designing new prototypes
starting from existing sophisticated programming environments
that we can find in standard (sequential)
object-oriented programming languages
(namely Smalltalk-80\footnote{Smalltalk-80 is a trade mark
	of Parc Place Systems.}).

Our starting point is a testbed for object-oriented concurrent languages
based on Smalltalk-80. This system (namely Actalk)
focuses on {\em actor}-based languages and gives a good integration of {\em actors}
into the Smalltalk-80 system.
We naturally came to reuse the standard Smalltalk-80
programming environment tools and to customize them to the
specificities of actors.
            
In this paper, we describe why and how we customize
the Model View Controller architecture to provide user-interfaces on actors,
and the scheduler to simulate concurrent execution of actors.
Other tools such as stepper and chronogram are also discussed.
We then summarize our experience in building and using this prototype
programming environment to prospect future programming environments
for object-based concurrent systems.