Microsoft Management Console loads DLLs into the process, it does not use a separate process for the snap-in. (Just checked this in a debugger) As for why the

Microsoft Management Console loads DLLs into the process, it does not use a separate process for the snap-in. (Just checked this in a debugger) As for why there would be bad performance for putting a window into another process's window, I can only speculate. It takes something like 10000+ CPU cycles for Windows to finish switching to a different thread or process. If this is happening for every message that is handled by both the parent and the child window, that would be a lot of overhead. I haven't checked if the Out-of-process webview is the EXE that owns the window or not.