What is Ctrl+D shortcut key used for TeamViewer?

I was trying to remote to another pc to use Visual Studio, as I wanted to use (Ctrl+K, Ctrl+D) to format my codes but Ctrl+D have trigger a nudge sound for TeamViewer everytime I pressed, I could not find any appearance or sign after hearing a nudge. Does anyone know what Ctrl+D actually do for TeamViewer and how can I remove or modify this key bind?