Host: how to achieve DSP - UI communication



I am developing a host. I used editorhost.ccp as an example. So far, everything is ok but I have one plugin with the UI functioning partially. After some exchange with the vendor, he told me that my host does not implement “separate dsp-ui” communication properly. I concluded that this separation of ui and dsp is not implemented in editorhost example. As a matter of fact the plugin as the same problem when launched with editorhost.exe. So i have 3 questions:

  1. Am I right in saying that dsp-ui communication is not implemented in editorhost?
  2. What do I have to add to editorhost.cpp to do it properly?
  3. Is there a place I should look in the documentation that explains that?

So far, I have found that maybe kDistributable or classFlags (or both) could be related to this issue but both are not documented in VST - VST 3 Developer Portal and poorly documented in VST 3 SDK: Introduction

Thank you