You can switch between Adaptive and Maximum LOD for selected feature classes.
The default is
Adaptive LOD. When you select
Maximum LOD for the selected feature type, its members will always display at the highest detail level available.
in the Utility Bar to display the Model Explorer panel.
Maximum LOD for the feature types to set. In example below, Points of Interest feature class is set to Maximum LOD. 
There is a single Maximum LOD setting for all Surface layers (Point Clouds, Terrain, Coverage, Railways, Roads and Water Areas). Other feature types have individual settings.