Running both VST2 and VST3 versions of Waves plug-ins in the same SONAR session is currently not supported by Waves. Mixing and matching VST2 and VST3 plugins will likely result in the plugins crashing or the UI not drawing.
A mix of VST2 and VST3 Waves plugins can happen under the following scenarios:
- You have "Replace VST2 Plugins when opening projects" (under Edit > Preferences > File - VST Settings) turned off, open a project containing VST2 versions of Waves plugins and later add a VST3 Waves plugin
- You have "Hide Related VST2 Plugins" disabled (under Edit > Preferences > File - VST Settings) and open both VST2 and VST3 plugins
Note that this limitation applies to all projects that are open in SONAR not just mixing and matching in the same project. Additionally if you are experiencing Waves plugin parameters being lost, make sure you have the SONAR X3e update installed.