SELECTIONPREVIEW (system variable) is used to control the display of selection preview.
The initial value for SELECTIONPREVIEW is 3, which means the preview effect is on.
When we hover our mouse over an object, the object will be highlighted, as shown in the following,
If the value is set to 0, the preview effect is turned off. You won’t get any preview effect when you hover that cursor.
If the value is set to 1, the preview effect is on when there is no active command.
That’s why we can see the preview until the Move command is executed.
If the value is set to 2, the preview effect is on when prompted to select object.
We can only see the preview when prompted to select an object.