Jerry Bartels of Autodesk shows how to customize the rollover ToolTips in the Civil 3D CUI (and any ACAD-based application) to include additional property information.
From the Jerry's YouTube Channel.
and the Civil Immersion blog.
Technically, I'd call this personalization not customization unless you're going to share the CUI tweaks.
Because of WTMI in Civil 3D for some Features, folks also ask how to turn off the ToolTips.
You can change this for individual named Features in the Info tab or via the Feature Settings for all Features of a Feature type.