Dialog box keyboard commands

TAB: Move to the next control in the dialog box
SHIFT+TAB: Move to the previous control in the dialog box
SPACEBAR: If the current control is a button, this clicks the button. If the current control is a check box, this toggles the check box. If the current control is an option, this selects the option.
ENTER: Equivalent to clicking the selected button (the button with the outline)
ESC: Equivalent to clicking the Cancel button
ALT+underlined letter in dialog box item: Move to the corresponding item