At some point in the reqs process we decided that GMPI wasn't going to get too deep into GUI issues, because the issues were probably as complex as all of the rest of GMPI combined. Now we are involved in a debate about GUIs. Let's please take a deep breath, and slow down. I'd much rather argue about code formatting. :-) What I thought we agreed is required: [1] GUI is a separate abstraction from DSP. [2] GMPI defines some mechanism to "listen" and "notify" parameter changes. This mechanism needs to allow out of process communication, because some plugins may want to work this way. That's it. What's all the fuss?