Index: trunk/src/conf.c
===================================================================
--- trunk/src/conf.c	(revision 1915)
+++ trunk/src/conf.c	(revision 1916)
@@ -379,27 +379,15 @@
 	return res;
 }
 
-/* merge main subtree of a patch */
-int conf_merge_patch_recurse(lht_node_t *sect, int default_prio, conf_policy_t default_policy, const char *path_prefix)
-{
-	lht_dom_iterator_t it;
-	lht_node_t *n, *h;
-	char path[256], *pathe;
-	char name[256], *namee;
-	int nl, ppl = strlen(path_prefix), res = 0;
-	conf_native_t *target;
+int conf_merge_patch_recurse(lht_node_t *sect, int default_prio, conf_policy_t default_policy, const char *path_prefix);
 
-	memcpy(path, path_prefix, ppl);
-	path[ppl] = '/';
-	pathe = path + ppl + 1;
+void d1() {}
 
-	for(n = lht_dom_first(&it, sect); n != NULL; n = lht_dom_next(&it)) {
-		nl = strlen(n->name);
-		memcpy(pathe, n->name, nl);
-		namee = pathe+nl;
-		*namee = '\0';
-		target = conf_get_field(path);
-
+int conf_merge_patch_item(const char *path, lht_node_t *n, int default_prio, conf_policy_t default_policy)
+{
+	conf_native_t *target = conf_get_field(path);
+	int res = 0;
+if (strstr(path, "unit") != NULL) d1();
 		switch(n->type) {
 			case LHT_TEXT:
 				if (target == NULL) {
@@ -426,6 +414,29 @@
 					hid_cfg_error(n, "Attempt to initialize a scalar with a list - this node should be a text node\n");
 				break;
 		}
+	return res;
+}
+
+
+/* merge main subtree of a patch */
+int conf_merge_patch_recurse(lht_node_t *sect, int default_prio, conf_policy_t default_policy, const char *path_prefix)
+{
+	lht_dom_iterator_t it;
+	lht_node_t *n, *h;
+	char path[256], *pathe;
+	char name[256], *namee;
+	int nl, ppl = strlen(path_prefix), res = 0;
+
+	memcpy(path, path_prefix, ppl);
+	path[ppl] = '/';
+	pathe = path + ppl + 1;
+
+	for(n = lht_dom_first(&it, sect); n != NULL; n = lht_dom_next(&it)) {
+		nl = strlen(n->name);
+		memcpy(pathe, n->name, nl);
+		namee = pathe+nl;
+		*namee = '\0';
+		res |= conf_merge_patch_item(path, n, default_prio, default_policy);
 	}
 	return res;
 }
@@ -458,14 +469,20 @@
 {
 	int n, ret = 0;
 	for(n = 0; n < CFR_max; n++) {
-		lht_node_t *r;
+		lht_node_t *r, *r2;
 		if (conf_root[n] == NULL)
 			continue;
 		for(r = conf_root[n]->root->data.list.first; r != NULL; r = r->next) {
-			if (path != NULL)
-				r = lht_tree_path_(r->doc, r, path, 1, 0, NULL);
-			if ((r != NULL) && (conf_merge_patch(r, conf_default_prio[n]) != 0))
-				ret = -1;
+			if (path != NULL) {
+				conf_policy_t gpolicy = POL_OVERWRITE;
+				r2 = lht_tree_path_(r->doc, r, path, 1, 0, NULL);
+				get_hash_policy(&gpolicy, r, "policy");
+				if ((r2 == NULL) || (conf_merge_patch_item(path, r2, conf_default_prio[n], gpolicy) != 0))
+					ret = -1;
+			}
+			else
+				if (conf_merge_patch(r, conf_default_prio[n]) != 0)
+					ret = -1;
 		}
 	}
 	return ret;
@@ -506,15 +523,24 @@
 			(*h)->notify_conf_changed();
 }
 
-void conf_update()
+void conf_update(const char *path)
 {
-	/* clear all memory-bin data first */
-	htsp_entry_t *e;
-	conf_fields_foreach(e)
-		conf_field_clear(e->value);
+	/* clear memory-bin data first */
+	if (path == NULL) {
+		htsp_entry_t *e;
+		conf_fields_foreach(e)
+			conf_field_clear(e->value);
+	}
+	else {
+		conf_native_t *n;
+		n = conf_get_field(path);
+		if (n == NULL)
+			return;
+		conf_field_clear(n);
+	}
 
 	/* merge all memory-lht data to memory-bin */
-	conf_merge_all(NULL);
+	conf_merge_all(path);
 	conf_core_postproc();
 	conf_notify_hids();
 }
Index: trunk/src/conf.h
===================================================================
--- trunk/src/conf.h	(revision 1915)
+++ trunk/src/conf.h	(revision 1916)
@@ -132,7 +132,7 @@
 void conf_load_all(void);
 
 /* Update the binary representation from the memory-lht representation */
-void conf_update(void);
+void conf_update(const char *path);
 
 conf_native_t *conf_get_field(const char *path);
 void conf_reg_field_(void *value, int array_size, conf_native_type_t type, const char *path, const char *desc);
@@ -218,18 +218,13 @@
 	char *__tmp__ = pcb_strdup_printf(fmt, new_val); \
 	conf_set(CFR_DESIGN, path, -1, __tmp__, POL_OVERWRITE); \
 	free(__tmp__); \
+	conf_update(path); \
 } while(0)
 
-#define conf_SET_design(path, fmt, new_val) \
-do { \
-	conf_set_design(path, fmt, new_val); \
-	conf_update(); \
-} while(0)
-
 #define conf_set_editor(field, val) \
 do { \
 	conf_set(CFR_DESIGN, "editor/" #field, -1, val ? "1" : "0", POL_OVERWRITE); \
-	conf_update(); \
+	conf_update("editor/" #field); \
 } while(0)
 
 #define conf_toggle_editor(field) \
Index: trunk/src/conf_act.c
===================================================================
--- trunk/src/conf_act.c	(revision 1915)
+++ trunk/src/conf_act.c	(revision 1916)
@@ -87,7 +87,7 @@
 			Message("conf(set) failed.\n");
 			return 1;
 		}
-		conf_update();
+		conf_update(path);
 	}
 
 	else if (NSTRCMP(cmd, "toggle") == 0) {
@@ -128,7 +128,7 @@
 			Message("Can not toggle '%s': failed to set new value\n", argv[1]);
 			return 1;
 		}
-		conf_update();
+		conf_update(argv[1]);
 	}
 
 	else if (NSTRCMP(cmd, "toggle") == 0) {
@@ -140,7 +140,7 @@
 			return 1;
 		}
 		conf_reset(role, "<action>");
-		conf_update();
+		conf_update(argv[1]);
 	}
 
 	else {
Index: trunk/src/gui_act.c
===================================================================
--- trunk/src/gui_act.c	(revision 1915)
+++ trunk/src/gui_act.c	(revision 1916)
@@ -1062,7 +1062,7 @@
 	case LINE_TYPE:
 		notify_crosshair_change(false);
 		conf_set_design("design/line_thickness", "%$mS", ((LineTypePtr) ptr2)->Thickness);
-		conf_SET_design("design/keepaway", "%$mS", ((LineTypePtr) ptr2)->Clearance / 2);
+		conf_set_design("design/keepaway", "%$mS", ((LineTypePtr) ptr2)->Clearance / 2);
 		layer = (LayerTypePtr) ptr1;
 		if (conf_core.editor.mode != LINE_MODE)
 			SetMode(LINE_MODE);
@@ -1073,7 +1073,7 @@
 	case ARC_TYPE:
 		notify_crosshair_change(false);
 		conf_set_design("design/line_thickness", "%$mS", ((ArcTypePtr) ptr2)->Thickness);
-		conf_SET_design("design/keepaway", "%$mS", ((ArcTypePtr) ptr2)->Clearance / 2);
+		conf_set_design("design/keepaway", "%$mS", ((ArcTypePtr) ptr2)->Clearance / 2);
 		layer = (LayerTypePtr) ptr1;
 		if (conf_core.editor.mode != ARC_MODE)
 			SetMode(ARC_MODE);
@@ -1089,7 +1089,7 @@
 		notify_crosshair_change(false);
 		conf_set_design("design/via_thickness", "%$mS", ((PinTypePtr) ptr2)->Thickness);
 		conf_set_design("design/via_drilling_hole", "%$mS", ((PinTypePtr) ptr2)->DrillingHole);
-		conf_SET_design("design/keepaway", "%$mS", ((PinTypePtr) ptr2)->Clearance / 2);
+		conf_set_design("design/keepaway", "%$mS", ((PinTypePtr) ptr2)->Clearance / 2);
 		if (conf_core.editor.mode != VIA_MODE)
 			SetMode(VIA_MODE);
 		notify_crosshair_change(true);
Index: trunk/src/main.c
===================================================================
--- trunk/src/main.c	(revision 1915)
+++ trunk/src/main.c	(revision 1916)
@@ -495,7 +495,7 @@
 
 	/* plugins may have installed their new fields, reinterpret the config
 	   (memory lht -> memory bin) to get the new fields */
-	conf_update();
+	conf_update(NULL);
 
 	if (main_action != NULL) {
 		hid_parse_command(main_action);
Index: trunk/src/set.c
===================================================================
--- trunk/src/set.c	(revision 1915)
+++ trunk/src/set.c	(revision 1916)
@@ -79,7 +79,7 @@
 void SetLineSize(Coord Size)
 {
 	if (Size >= MIN_LINESIZE && Size <= MAX_LINESIZE) {
-		conf_SET_design("design/line_thickness", "%$mS", Size);
+		conf_set_design("design/line_thickness", "%$mS", Size);
 		if (conf_core.editor.auto_drc)
 			FitCrosshairIntoGrid(Crosshair.X, Crosshair.Y);
 	}
@@ -91,7 +91,7 @@
 void SetViaSize(Coord Size, bool Force)
 {
 	if (Force || (Size <= MAX_PINORVIASIZE && Size >= MIN_PINORVIASIZE && Size >= conf_core.design.via_drilling_hole + MIN_PINORVIACOPPER)) {
-		conf_SET_design("design/via_thickness", "%$mS", Size);
+		conf_set_design("design/via_thickness", "%$mS", Size);
 	}
 }
 
@@ -101,7 +101,7 @@
 void SetViaDrillingHole(Coord Size, bool Force)
 {
 	if (Force || (Size <= MAX_PINORVIASIZE && Size >= MIN_PINORVIAHOLE && Size <= conf_core.design.via_thickness - MIN_PINORVIACOPPER)) {
-		conf_SET_design("design/via_drilling_hole", "%$mS", Size);
+		conf_set_design("design/via_drilling_hole", "%$mS", Size);
 	}
 }
 
@@ -110,7 +110,7 @@
 	conf_set_design("design/line_thickness", "%$mS", rst->Thick);
 	conf_set_design("design/via_thickness", "%$mS", rst->Diameter);
 	conf_set_design("design/via_drilling_hole", "%$mS", rst->Hole);
-	conf_SET_design("design/keepaway", "%$mS", rst->Keepaway);
+	conf_set_design("design/keepaway", "%$mS", rst->Keepaway);
 }
 
 /* ---------------------------------------------------------------------------
@@ -119,7 +119,7 @@
 void SetKeepawayWidth(Coord Width)
 {
 	if (Width <= MAX_LINESIZE) {
-		conf_SET_design("design/keepaway", "%$mS", Width);
+		conf_set_design("design/keepaway", "%$mS", Width);
 	}
 }
 
@@ -129,7 +129,7 @@
 void SetTextScale(int Scale)
 {
 	if (Scale <= MAX_TEXTSCALE && Scale >= MIN_TEXTSCALE) {
-		conf_SET_design("design/text_scale", "%d", Scale);
+		conf_set_design("design/text_scale", "%d", Scale);
 	}
 }
 
@@ -166,7 +166,7 @@
 {
 	if (Number >= 0 && Number < MAX_BUFFER) {
 		conf_set_design("editor/buffer_number", "%d", Number);
-		conf_update();
+		conf_update("editor/buffer_number");
 
 		/* do an update on the crosshair range */
 		SetCrosshairRangeToBuffer();
@@ -234,7 +234,7 @@
 		Crosshair.AttachedLine.Point1.Y = Crosshair.AttachedLine.Point2.Y = Crosshair.AttachedBox.Point1.Y;
 		sprintf(sMode, "%d", Mode);
 		conf_set(CFR_DESIGN, "editor/mode", -1, sMode, POL_OVERWRITE);
-		conf_update();
+		conf_update("editor/mode");
 		AdjustAttachedObjects();
 	}
 	else {
@@ -252,7 +252,7 @@
 
 	sprintf(sMode, "%d", Mode);
 	conf_set(CFR_DESIGN, "editor/mode", -1, sMode, POL_OVERWRITE);
-	conf_update();
+	conf_update("editor/mode");
 
 	if (Mode == PASTEBUFFER_MODE)
 		/* do an update on the crosshair range */
Index: trunk/src_plugins/export_gerber/gerber.c
===================================================================
--- trunk/src_plugins/export_gerber/gerber.c	(revision 1915)
+++ trunk/src_plugins/export_gerber/gerber.c	(revision 1916)
@@ -599,7 +599,7 @@
 	maybe_close_f(f);
 	f = NULL;
 	hid_restore_layer_ons(save_ons);
-	conf_update(); /* resotre forced sets */
+	conf_update(NULL); /* resotre forced sets */
 }
 
 static void gerber_parse_arguments(int *argc, char ***argv)
Index: trunk/src_plugins/export_png/png.c
===================================================================
--- trunk/src_plugins/export_png/png.c	(revision 1915)
+++ trunk/src_plugins/export_png/png.c	(revision 1916)
@@ -520,7 +520,7 @@
 	hid_expose_callback(&png_hid, bounds, 0);
 
 	memcpy(LayerStack, saved_layer_stack, sizeof(LayerStack));
-	conf_update(); /* restore forced sets */
+	conf_update(NULL); /* restore forced sets */
 }
 
 static void blend(color_struct * dest, float a_amount, color_struct * a, color_struct * b)
Index: trunk/src_plugins/export_ps/eps.c
===================================================================
--- trunk/src_plugins/export_ps/eps.c	(revision 1915)
+++ trunk/src_plugins/export_ps/eps.c	(revision 1916)
@@ -303,7 +303,7 @@
 	fprintf(f, "%%%%EOF\n");
 
 	memcpy(LayerStack, saved_layer_stack, sizeof(LayerStack));
-	conf_update(); /* restore forced sets */
+	conf_update(NULL); /* restore forced sets */
 }
 
 static void eps_do_export(HID_Attr_Val * options)
Index: trunk/src_plugins/export_ps/ps.c
===================================================================
--- trunk/src_plugins/export_ps/ps.c	(revision 1915)
+++ trunk/src_plugins/export_ps/ps.c	(revision 1916)
@@ -700,7 +700,7 @@
 		fprintf(the_file, "showpage\n");
 
 	memcpy(LayerStack, saved_layer_stack, sizeof(LayerStack));
-	conf_update(); /* restore forced sets */
+	conf_update(NULL); /* restore forced sets */
 }
 
 static void ps_do_export(HID_Attr_Val * options)
Index: trunk/src_plugins/fontmode/fontmode.c
===================================================================
--- trunk/src_plugins/fontmode/fontmode.c	(revision 1915)
+++ trunk/src_plugins/fontmode/fontmode.c	(revision 1916)
@@ -87,7 +87,7 @@
 	conf_set_design("design/bloat", "%s", "1"); PCB->Bloat = 1;
 	conf_set_design("design/shrink", "%s", "1"); PCB->Shrink = 1;
 	conf_set_design("design/min_wid", "%s", "1"); PCB->minWid = 1;
-	conf_SET_design("design/min_slk", "%s", "1"); PCB->minSlk = 1;
+	conf_set_design("design/min_slk", "%s", "1"); PCB->minSlk = 1;
 
 	MoveLayerToGroup(max_copper_layer + COMPONENT_LAYER, 0);
 	MoveLayerToGroup(max_copper_layer + SOLDER_LAYER, 1);
Index: trunk/src_plugins/hid_gtk/gtkhid-main.c
===================================================================
--- trunk/src_plugins/hid_gtk/gtkhid-main.c	(revision 1915)
+++ trunk/src_plugins/hid_gtk/gtkhid-main.c	(revision 1916)
@@ -137,7 +137,7 @@
 	ghid_pcb_to_event_coords(center_x, center_y, &widget_x, &widget_y);
 
 	conf_set_design("editor/view/flip_x", "%d", conf_core.editor.view.flip_x != flip_x);
-	conf_SET_design("editor/view/flip_y", "%d", conf_core.editor.view.flip_y != flip_y);
+	conf_set_design("editor/view/flip_y", "%d", conf_core.editor.view.flip_y != flip_y);
 
 	/* Pan the board so the center location remains in the same place */
 	ghid_pan_view_abs(center_x, center_y, widget_x, widget_y);
@@ -1624,7 +1624,7 @@
 	if (new_unit != NULL && new_unit->allow != NO_PRINT) {
 #warning TODO: decide what to do with this: some fields are just overwritten by hand
 		conf_set(CFR_DESIGN, "editor/grid_unit", -1, argv[0], POL_OVERWRITE);
-		conf_update();
+		conf_update("editor/grid_unit");
 		AttributePut(PCB, "PCB::grid::unit", argv[0]);
 	}
 
Index: trunk/src_plugins/hid_gtk/gui-config.c
===================================================================
--- trunk/src_plugins/hid_gtk/gui-config.c	(revision 1915)
+++ trunk/src_plugins/hid_gtk/gui-config.c	(revision 1916)
@@ -762,7 +762,7 @@
 	conf_set(CFR_PROJECT, "design/max_width", -1, s, POL_OVERWRITE);
 	pcb_sprintf(s, "%$mS", (new_board_height));
 	conf_set(CFR_PROJECT, "design/max_height", -1, s, POL_OVERWRITE);
-	conf_update();
+	conf_update("design/max_height");
 
 #warning TODO: what? this could be removed once user can select where to save
 	active = gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(use_board_size_default_button));
@@ -779,7 +779,7 @@
 		conf_set_design("design/min_slk", "%$mS", PCB->minSlk);
 		conf_set_design("design/poly_isle_area", "%f", PCB->IsleArea);
 		conf_set_design("design/min_drill", "%$mS", PCB->minDrill);
-		conf_SET_design("design/min_ring", "%$mS", PCB->minRing);
+		conf_set_design("design/min_ring", "%$mS", PCB->minRing);
 		ghidgui->config_modified = TRUE;
 	}
 
@@ -1512,7 +1512,7 @@
 
 	printf("COLOR IDX: %d\n", ci->idx);
 	conf_set(CFR_PROJECT, ci->cfg->hash_path, ci->idx, str, POL_OVERWRITE);
-	conf_update();
+	conf_update(ci->cfg->hash_path);
 
 #warning TODO: check whether we need to free this
 //	g_free(str);
Index: trunk/src_plugins/hid_gtk/gui-top-window.c
===================================================================
--- trunk/src_plugins/hid_gtk/gui-top-window.c	(revision 1915)
+++ trunk/src_plugins/hid_gtk/gui-top-window.c	(revision 1916)
@@ -739,7 +739,7 @@
 static void route_styles_edited_cb(GHidRouteStyleSelector * rss, gboolean save, gpointer data)
 {
 	if (save) {
-		conf_SET_design(conf_core.design.routes, "%s", make_route_string(PCB->RouteStyle, NUM_STYLES));
+		conf_set_design(conf_core.design.routes, "%s", make_route_string(PCB->RouteStyle, NUM_STYLES));
 		ghidgui->config_modified = TRUE;
 		ghid_config_files_write();
 	}
Index: trunk/src_plugins/hid_lesstif/dialogs.c
===================================================================
--- trunk/src_plugins/hid_lesstif/dialogs.c	(revision 1915)
+++ trunk/src_plugins/hid_lesstif/dialogs.c	(revision 1916)
@@ -1069,7 +1069,7 @@
 	conf_set_design("design/min_wid", "%s", sz_drc_wid);
 	conf_set_design("design/min_slk", "%s", sz_drc_slk);
 	conf_set_design("design/min_drill", "%s", sz_drc_drill);
-	conf_SET_design("design/min_ring", "%s", sz_drc_ring);
+	conf_set_design("design/min_ring", "%s", sz_drc_ring);
 
 	SetCrosshairRange(0, 0, PCB->MaxWidth, PCB->MaxHeight);
 	lesstif_pan_fixup();
Index: trunk/src_plugins/hid_lesstif/styles.c
===================================================================
--- trunk/src_plugins/hid_lesstif/styles.c	(revision 1915)
+++ trunk/src_plugins/hid_lesstif/styles.c	(revision 1916)
@@ -151,16 +151,16 @@
 	n = GetValueEx(s, NULL, NULL, NULL, unit->suffix, NULL);
 	switch (i) {
 	case SSthick:
-		conf_SET_design("design/line_thickness", "%s", s);
+		conf_set_design("design/line_thickness", "%s", s);
 		break;
 	case SSdiam:
-		conf_SET_design("design/via_thickness", "%s", s);
+		conf_set_design("design/via_thickness", "%s", s);
 		break;
 	case SShole:
-		conf_SET_design("design/via_drilling_hole", "%s", s);;
+		conf_set_design("design/via_drilling_hole", "%s", s);;
 		break;
 	case SSkeep:
-		conf_SET_design("design/keepaway", "%s", s);;
+		conf_set_design("design/keepaway", "%s", s);;
 		break;
 	}
 	update_style_buttons();
Index: trunk/src_plugins/io_pcb/parse_l.c
===================================================================
--- trunk/src_plugins/io_pcb/parse_l.c	(revision 1915)
+++ trunk/src_plugins/io_pcb/parse_l.c	(revision 1916)
@@ -2530,7 +2530,7 @@
 		/* load config nodes not disabled above, from optional attributes */
 		io_pcb_attrib_a2c(Ptr);
 
-		conf_update();
+		conf_update(NULL);
 	}
 	return retval;
 }
Index: trunk/src_plugins/renumber/renumber.c
===================================================================
--- trunk/src_plugins/renumber/renumber.c	(revision 1915)
+++ trunk/src_plugins/renumber/renumber.c	(revision 1916)
@@ -297,7 +297,7 @@
 	fclose(out);
 
 	/* restore the unique flag setting */
-	conf_update();
+	conf_update(NULL);
 
 	if (changed) {