You can modify the user interface of an MCG tool by entering standard MAXScript in the Custom UI property of the graph to redefine its rollout.
The default rollout simply lists the graph's parameters in depth-first order, and assigns the default UI control for their data types. By editing the Custom UI property, you can change labels, reorder parameters, modify the default values and ranges, define groups, change UI controls, and so on. For a description of all the possibilities, see the "Scripted Utilities and Rollouts" section of the MAXScript Help.
Every parameter in the graph must be included in the same rollout. However, you can define additional rollouts that are not associated with any parameter block (for example, labels and hyperlinks for information).
You can hide parameters by setting visible:false. Hidden UI controls still take up space in the rollout, but you can minimize this by placing them at the end and using layout parameters to make them as small as possible. Also, note that all graph parameters are always visible in the Track View and Motion panel.