What is menu bar?
A menu bar is a graphical user interface (GUI) component which
contains all the commands that may be executed according to the
current context of an application.
The menu bar typically appears at the top of the application
window and will display the primary commands such as File, Edit,
Tools and Help. Clicking one of these will reveal related commands
within a drop-down sub-menu. For instance, clicking File will
reveal the commands that may be executed upon files, such as New,
Open, Save, Print and Close. Some commands may reveal more specific
commands within another sub-menu.
Commands that are outwith the current context of the application
are typically disabled. For instance, if there are no files
currently open, then the Save, Print and Close commands will be
disabled. As the context of the application shifts, the menu bar
will adjust accordingly, enabling and disabling commands as befits
the current context. In some cases, commands may be hidden
completely rather than simply disabled, only becoming visible when
they are within context. For instance, when you open a specific
type of document, commands that are specific to that type of
document will be made visible. And if you switch between multiple
document types, the menu bar will adjust accordingly.
In modern GUIs, the menu bar is often hidden in favour of more
graphical components such as tool bars and ribbon bars.