Index: trunk/src/data.c
===================================================================
--- trunk/src/data.c	(revision 766)
+++ trunk/src/data.c	(revision 767)
@@ -251,3 +251,28 @@
 	camv->lysel = idx;
 	rnd_event(&camv->hidlib, CAMV_EVENT_LAYER_SELECTED, "i", idx);
 }
+
+void camv_data_reverse_layers(camv_design_t *camv, int inhibit_ev)
+{
+	vtp0_t tmp = {0};
+	long n, end, i;
+
+	/* go backward from the end, look for non-sub-layers to copy each
+	   "layer group" at the end of tmp */
+	end = camv->layers.used;
+	for(n = camv->layers.used-1; n >= 0; n--) {
+		const camv_layer_t *ly = camv->layers.array[n];
+		if (!ly->sub) {
+			for(i = n; i < end; i++)
+				vtp0_append(&tmp, camv->layers.array[i]);
+			end = n;
+		}
+	}
+
+	vtp0_uninit(&camv->layers);
+	memcpy(&camv->layers, &tmp, sizeof(vtp0_t));
+
+	if (!inhibit_ev)
+		rnd_event(&camv->hidlib, CAMV_EVENT_LAYERS_CHANGED, NULL);
+}
+
Index: trunk/src/data.h
===================================================================
--- trunk/src/data.h	(revision 766)
+++ trunk/src/data.h	(revision 767)
@@ -113,6 +113,7 @@
 void camv_group_load_begin(camv_design_t *camv);
 void camv_group_load_end(camv_design_t *camv);
 
+void camv_data_reverse_layers(camv_design_t *camv, int inhibit_ev);
 
 #define camv_hid_redraw(camv) rnd_render->invalidate_all(rnd_render)