You can customize the default Mudbox marking menus by editing their XML source files.
You can find the marking menu source files in the following locations, and edit them using any text editor.
For example, on Windows 7, you can open the files with administrator privileges by right-clicking the shortcut for the Notepad program, then selecting Run as Administrator. You can then open, edit, and save the XML files in Notepad.
Edit the XML files to make any of the following changes: