The All Layers On and All Layers Off buttons provide a rapid means of toggling all the layers in the Layer List to be visible or not visible. After using either the All Layers On or All Layers Off buttons, the user may then toggle individual layers selectively. When layers are toggled, the Refresh Map button will highlight. Changes tot he visibility settings will not take effect until the user clicks the Refresh Map button. Note: There must be at least one layer visible at all times before the Refresh Map operation will work.
