I’m on MacOS 10.15.2 Catalina running Renoise 3.2.1 (licensed).
When I enter fullscreen mode in Renoise (alt+enter), the MacOS Dock remains visible on the bottom, covering some of the controls. It’s generally the case for MacOS apps with fullscreen modes that the dock disappears completely and becomes inaccessible as long as the app is in fullscreen (you need to exit fullscreen mode to access it again).
I’ve noticed this previously when I first ran Renoise on a Mac, but now that I’m primarily using Mac, it’s kind of an issue.
This is also the case in Catalina 10.15.3.