Usually because the command doesn't apply to a specific situation.For example: in MS-Word, the "Copy" command copies the selected text to an intermediate storage area called the "Clipboard". If NO text is selected (the cursor is between two letters), then there is nothing to copy, and the command is grayed out.
a Menu.
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.
It depends on the context. Someone may be unavailable because they are away for some reason. A service may be unavailable due to technical difficulties. An item may be unavailable because it is out of stock.
It´s because you´re game may be corrupted!
Sugar was unavailable so the Sumerians used Honey.
yes
Community - 2009 Curriculum Unavailable 3-19 was released on: USA: 10 May 2012
You may have a breakfast menu, lunch menu, desert menu, wine menu etc.
Soldier is on transitional leave
Love for Sail - 2012 Emotionally Unavailable 1-7 was released on: USA: May 2012
The Windows task player can be accessed by holding down the 'Ctrl' 'Alt' and 'Delete' buttons simultaneously. The task manager may appear or there may be a menu from which the task manager can be selected.
The Law Commands - 1937 was released on: USA: 7 May 1937