Click Tools > Customize > NC Toolbar/Menu, then click the machining type to customize.
A dialog appears that lets you choose which buttons to keep on the toolbar, or insert separators, or reorder the buttons. For example, imagine you do only 2-axis drilling. Click Tools > Customize > NC Toolbar/Menu > 2 Axis. Remove all buttons except Drill. The next time you click NC > 2 Axis, only the Drill button appears.