Disabled Options in OS X El Capitan
Menu items that appear in black on an OS X El Capitan menu are currently available. Menu items that aren’t currently available are grayed out, meaning that they’re disabled for the time being. You can’t select a disabled menu item.
In this figure, the File menu on the left is pulled down while nothing is selected in the Finder; this is why many of the menu items are disabled (in gray). These items are disabled because an item (such as a window or icon) must be selected for you to use one of these menu items. For example, the Show Original command is grayed out because it works only if the selected item is an alias.
On the right side of the figure, a document was selected before the menu was pulled down; notice that many of the formerly disabled commands are enabled when an icon is selected. (The Show Original command is still grayed out because the selected icon is not an alias.)
Finally, notice that items that end in an ellipsis ( . . . ), such as the Burn “I Am a Document” to Disc command, will open a dialog with additional options.