The Optimized Fence Clipping preference in the Operation category of the Preferences dialog is on by default. This preference enables you to maintain closed shapes, solids, and surfaces when clipping those elements that cross a fence boundary.
There is a toggle that will allow you to fence clip elements in different fashions. Depending on how you want to your fence clipping operation to perform, it can automatically close shapes, surfaces and solids or you can trim the elements. Under Workspace > Preferences > Operation there is the option to Optimized Fence Clipping.
The operations copy, move, rotate, scale, mirror and stretch would all work similarly.
The following screen shots show you the end result of the Fence Clip Delete command. Both elements are going to be deleted by the fence using the clip mode.
If “Use Optimized Fence Clipping” is toggled off the fence clipping operation will drop the closed shapes to individual elements as shown below.
If “Use Optimized Fence Clipping” is toggled on the fence clipping operation will automatically close the shapes for you as shown below.