This has bugging me for the longest time and I finally clued in on the cause. AU plugins white out if the plugin editor calls centreWithSize() in its constructor. I know you don’t need this for a plugin as it pertains to positing the component within a parent, however it had been an overlooked residual of mine from an app conversion. Now, a VST3 plugin gracefully overlooks this and just works while AUs refuse to render (no paint() calls). Bug or feature? Thanks a bunch …