To Navigate Drop-Down Lists
A drop-down list is a control that you use to select one of several
available items. The drop-down list contains a button that you use to display
the available items. 
Figure 3–8  Sample Drop-Down List Box

The following table lists the keyboard shortcuts that you can use to
navigate a drop-down list.
| Keys  | Function  | 
| spacebar | This key performs one of the following functions:  
If the drop-down list is not open, this key opens the drop-down
list.
If the drop-down list is open, this key accepts the current
selection and closes the list.  | 
| up arrow | Select the previous list item.  | 
| down arrow | Select the next list item.  | 
| Esc | Close the list without changing
the selection.  |