Empty Layers - Displays a list of layers in the active drawing sheet which contain no objects.
Select All - Selects all layers in the Empty Layers list. By default, all layers are selected when you first open the dialog box.
Clear All - De-selects all the layers in the Empty Layers list so that none of them are removed when you click OK.
The dialog box will not list the Active Layer (if it does not contain any data) as a layer that can be deleted.
The dialog box displays only when empty layers exist in the active drawing sheet. If no empty layers exist, the following message is displayed instead: