Index: trunk/src/board.h
===================================================================
--- trunk/src/board.h	(revision 6104)
+++ trunk/src/board.h	(revision 6105)
@@ -95,7 +95,7 @@
 	  IsleArea,										/* minimum poly island to retain */
 	  ThermScale;									/* scale factor used with thermals */
 	pcb_font_t Font;
-	pcb_layer_group_t LayerGroups;
+	pcb_layer_stack_t LayerGroups;
 	vtroutestyle_t RouteStyle;
 	pcb_lib_t NetlistLib[PCB_NUM_NETLISTS];
 	pcb_ratspatch_line_t *NetlistPatches, *NetlistPatchLast;
Index: trunk/src/global_typedefs.h
===================================================================
--- trunk/src/global_typedefs.h	(revision 6104)
+++ trunk/src/global_typedefs.h	(revision 6105)
@@ -26,7 +26,7 @@
 
 typedef struct pcb_board_s pcb_board_t;
 typedef struct pcb_data_s pcb_data_t;
-typedef struct pcb_layer_group_s pcb_layer_group_t;
+typedef struct pcb_layer_stack_s pcb_layer_stack_t;
 typedef struct pcb_layer_s pcb_layer_t;
 typedef struct pcb_buffer_s pcb_buffer_t;
 typedef struct pcb_net_s pcb_net_t;
Index: trunk/src/layer.c
===================================================================
--- trunk/src/layer.c	(revision 6104)
+++ trunk/src/layer.c	(revision 6105)
@@ -144,7 +144,7 @@
 	return pcb_true;
 }
 
-int pcb_layer_parse_group_string(const char *s, pcb_layer_group_t *LayerGroup, int LayerN, int oldfmt)
+int pcb_layer_parse_group_string(const char *s, pcb_layer_stack_t *LayerGroup, int LayerN, int oldfmt)
 {
 	int group, member, layer;
 	pcb_bool c_set = pcb_false,						/* flags for the two special layers to */
@@ -152,7 +152,7 @@
 	int groupnum[PCB_MAX_LAYERGRP + 2];
 
 	/* clear struct */
-	memset(LayerGroup, 0, sizeof(pcb_layer_group_t));
+	memset(LayerGroup, 0, sizeof(pcb_layer_stack_t));
 
 	/* Clear assignments */
 	for (layer = 0; layer < PCB_MAX_LAYER + 2; layer++)
@@ -238,7 +238,7 @@
 
 	/* reset structure on error */
 error:
-	memset(LayerGroup, 0, sizeof(pcb_layer_group_t));
+	memset(LayerGroup, 0, sizeof(pcb_layer_stack_t));
 	return (1);
 }
 
Index: trunk/src/layer_grp.h
===================================================================
--- trunk/src/layer_grp.h	(revision 6104)
+++ trunk/src/layer_grp.h	(revision 6105)
@@ -36,7 +36,9 @@
  * layer group. A layer group identifies layers which are always switched
  * on/off together.
  */
-struct pcb_layer_group_s {
+
+/* layer stack: an ordered list of layer groups (physical layers). */
+struct pcb_layer_stack_s {
 	pcb_cardinal_t Number[PCB_MAX_LAYERGRP],      /* number of entries per groups */
 	  Entries[PCB_MAX_LAYERGRP][PCB_MAX_LAYER + 2];
 };
@@ -75,7 +77,7 @@
 
    OBSOLETE, do not use in new code: only the conf system and io_pcb
    may need this. */
-int pcb_layer_parse_group_string(const char *s, pcb_layer_group_t *LayerGroup, int LayerN, int oldfmt);
+int pcb_layer_parse_group_string(const char *s, pcb_layer_stack_t *LayerGroup, int LayerN, int oldfmt);
 
 #define GROUP_LOOP(data, group) do { 	\
 	pcb_cardinal_t entry; \
Index: trunk/src_plugins/djopt/djopt.c
===================================================================
--- trunk/src_plugins/djopt/djopt.c	(revision 6104)
+++ trunk/src_plugins/djopt/djopt.c	(revision 6105)
@@ -2461,7 +2461,7 @@
 static void grok_layer_groups()
 {
 	int i, j, f;
-	pcb_layer_group_t *l = &(PCB->LayerGroups);
+	pcb_layer_stack_t *l = &(PCB->LayerGroups);
 
 	solder_layer = component_layer = -1;
 	for (i = 0; i < pcb_max_copper_layer; i++) {
Index: trunk/src_plugins/hid_gtk/gui-config.c
===================================================================
--- trunk/src_plugins/hid_gtk/gui-config.c	(revision 6104)
+++ trunk/src_plugins/hid_gtk/gui-config.c	(revision 6105)
@@ -1189,7 +1189,7 @@
 
 static gint config_layer_group[PCB_MAX_LAYERGRP + 2];
 
-static pcb_layer_group_t layer_groups,	/* Working copy */
+static pcb_layer_stack_t layer_groups,	/* Working copy */
  *lg_monitor;										/* Keep track if our working copy */
 										/* needs to be changed (new layout) */
 
@@ -1260,7 +1260,7 @@
 	/* Construct a layer group string.  Follow logic in WritePCBDataHeader(),
 	   |  but use g_string functions.
 	 */
-static gchar *make_layer_group_string(pcb_layer_group_t * lg)
+static gchar *make_layer_group_string(pcb_layer_stack_t * lg)
 {
 	GString *string;
 	gint group, entry, layer;
Index: trunk/src_plugins/hid_lesstif/dialogs.c
===================================================================
--- trunk/src_plugins/hid_lesstif/dialogs.c	(revision 6104)
+++ trunk/src_plugins/hid_lesstif/dialogs.c	(revision 6105)
@@ -1347,7 +1347,7 @@
 {
 	int sets[PCB_MAX_LAYERGRP + 2][PCB_MAX_LAYER];
 	int i, j;
-	pcb_layer_group_t *l = &(PCB->LayerGroups);
+	pcb_layer_stack_t *l = &(PCB->LayerGroups);
 
 	if (!layer_groups_form)
 		return;
Index: trunk/src_plugins/io_pcb/file.c
===================================================================
--- trunk/src_plugins/io_pcb/file.c	(revision 6104)
+++ trunk/src_plugins/io_pcb/file.c	(revision 6105)
@@ -143,7 +143,7 @@
 }
 
 /* Returns pointer to private buffer */
-static char *LayerGroupsToString(pcb_layer_group_t *lg)
+static char *LayerGroupsToString(pcb_layer_stack_t *lg)
 {
 #if PCB_MAX_LAYER < 9998
 	/* Allows for layer numbers 0..9999 */