Note that in line 2-3 of program 2-2, we have indicated the keyboard accelerators for the two pages using the -underline option. The value of this option is the position of the character to be underlined in the string, where zero represents the first character. When the user presses $<$Alt-N$>$ or $<$Meta-N$>$ the ``Network'' page will be activated; on the other hand, if he presses $<$Alt-H$>$ or $<$Meta-H$>$ the ``Hard Disk'' page will be activated. The TixNoteBook widget will automatically create the keyboard bindings for these accelerators for us, in a way similar to what the menu widget does, so there is no need to set the keyboard bindings ourself.