Rollover tooltips display the current values of selected properties.
When customizing rollover tooltips, you can control which object types display a tooltip when the cursor hovers over an object in the drawing area and which properties are displayed. The properties that you can enable and disable are specific to the object you select, or general to all objects. General object properties include Layer, Linetype, Color, Lineweight, and so on.
Rollover tooltips are displayed for objects in the drawing area when the ROLLOVERTIPS system variable is set to 1.