Introducing AutoCAD 2011 - Introduction to AutoCAD 2011: 2D and 3D Design - page 13

Fig. 1.16 Part of the Options dialog
Note the following in the Options dialog ( Fig. 1.16 ) :
Tabs : A click on any of the tabs in the dialog brings a sub-dialog on screen.
Check boxes : A tick appearing in a check box indicates the function
described against the box is on. No tick and the function is off. A click
in a check box toggles between the feature being off or on.
Radio buttons : A black dot in a radio button indicates the feature
described is on. No dot and the feature is off.
Slider : A slider pointer can be dragged to change sizes of the feature
controlled by the slider.
Buttons at the left-hand end of the status bar
A number of buttons at the left-hand end of the status bar can be used for
toggling (turning on/off) various functions when operating within AutoCAD