Lidar Configuration
The Lidar section in the Configuration dialog controls the display and interpretation of Lidar classes and Return Types.
Access the Lidar Configuration by selecting the 
Configuration button from the File Toolbar or Tools menu, and navigating to the Lidar section. These settings are also available from the 
Filter button of the LiDAR Toolbar.
Classifications
Turn the display of Lidar classes on or off.
Context Menu
Enable All / Disable All
Use these buttons to quickly select or deselect all Lidar Classifications to make all visible or all filtered.
Return Types to Display
Turn the display of Return Types on or off. These settings apply to 3D point clouds that contain multiple returns, such as traditional aerial lidar data.
Update Return Number/ Count when Deleting Points
This setting will modify the return count (RETURN_CNT) and return number (RETURN_NUM) attributes of points when a point from the same pulse has been marked as deleted.
When a point is undeleted, the original return number and return counts will be restored for the related points.
Pulses Identified by GPS Time and ___
Select Only GPS Time, User Data, Point Source ID or Scanner Channel as the property to determine the point return type along with GPS time.
Restore Default Settings
This will turn all Lidar classes and Return Types on so they are visible, and reset all class names to the default ASPRS classification names.