The Realm War map Key window is used to show what the various symbols on the Realm War maps represent.
The window will appear when you click on the button labeled "Key" on one of the Realm War map windows.
There is nothing shown when the window is concealed. The window is invisible with no graphics or controls to minimize the amount of memory used. Nothing will appear on the screen when you attempt to activate the window.
This style includes a key symbol that will open an additional key window for the Labyrinth map areas.