hubert this is not that we did not look at Designer. We look at it. Now it is based on signal and signal use thisContext all the times if I recall correctly. In Pharo we are removing event mechanism, to use announcements. And we did not want to add yet another event mechanisms. Then we would like to have a uibuilder like in VW based on the reuse of composable ui elements. This is why the rmod team payed benjamin during the summer and before to work on Spec and an UIbuilder. Now benjamin did a lot but now he should go back to university. So the work around UIBuilder is not something that we will stop but it will be more time than expected. Please note that understanding what we really wanted and analyzing the available solution took us time. Now we have a nice first version of the system. Stef