Terraform4D has its own preference panel, located in the Cinema 4D Preferences dialog.
Terrain Subdivision Limit
The maximum number of segments allowed in a terrain can be set here. You will not be able to increase the segments of Terrain Objects beyond the set limit.
Loading a scene with a higher terrain resolution than allowed will decrease the segments to the maximum allowed value.
Tip: If you have a very beefy computer with lots of memory, you can increase this and see how far you can go. If your computer has little memory, think about decreasing this.
Show Blend Mode Icons on Operators
If this option is enabled, Operator Objects will indicate their blend mode with a little icon overlay in the Object Manager and Attribute Manager. Disable this, if you don't like it.
Show Terrain HUD
If this option is enabled, a HUD with information about the currently selected terrain(s) will be displayed in the viewport.
Default Blend Mode
Select a blend mode here, to make it the default blend mode for every Generator you create.
If you have used the ‘Set as Default...’ option in the Attribute Manager, the set default object will override the blend mode set here.