Thanks all so far,

My issue is not as much that I cannot load the plugin, I understand the standard example. My issue
is twofold:
a. when having selected a certain decoder, I want to be able to interact with a set of buttons and sliders on a screen, however, without
the main program having any knowledge of it (plugins, i.e. it should be possible to add decoders, without the main program having to
know on beforehand that such a decoder even exists)
b. When deallocating a decoder and creating a new decoder I want to have a fresh screen with the visuals of the new decoder. Is it possible to design
a screen for such a plugin (to be embedded on a fixed location in the main screen) using the designer

A pointer to any example (not begin the standard brushes etc plugin) would be appreciated

best
jan