diff --git a/gui.c b/gui.c
index ea7a03b..08b7cc6 100644
--- a/gui.c
+++ b/gui.c
@@ -322,11 +322,19 @@ static void do_build_frames(void)
 void change_world(void)
 {
 	struct bbox before, after;
+	int reachable_is_active;
 
 	inst_deselect();
 	status_begin_reporting();
 	before = inst_get_bbox();
+	reachable_is_active = reachable_pkg && reachable_pkg == active_pkg;
+	reachable_pkg = NULL;
 	instantiate();
+	if (reachable_is_active && reachable_pkg &&
+	     reachable_pkg != active_pkg) {
+		active_pkg = reachable_pkg;
+		instantiate();
+	}
 	after = inst_get_bbox();
 	label_in_box_bg(active_frame->label, COLOR_FRAME_SELECTED);
 	do_build_frames();
diff --git a/inst.c b/inst.c
index 24c1bab..7c58691 100644
--- a/inst.c
+++ b/inst.c
@@ -35,6 +35,7 @@
 struct inst *selected_inst = NULL;
 struct bbox active_frame_bbox;
 struct pkg *pkgs, *active_pkg, *curr_pkg;
+struct pkg *reachable_pkg = NULL;
 struct inst *frame_instantiating = NULL;
 
 static struct pkg *prev_pkgs;
@@ -1173,7 +1174,7 @@ void inst_end_frame(const struct frame *frame)
 /* ----- package ----------------------------------------------------------- */
 
 
-void inst_select_pkg(const char *name)
+void inst_select_pkg(const char *name, int active)
 {
 	struct pkg **pkg;
 	enum inst_prio prio;
@@ -1192,6 +1193,8 @@ void inst_select_pkg(const char *name)
 		(*pkg)->n_samples = n_samples;
 	}
 	curr_pkg = *pkg;
+	if (active && name)
+		reachable_pkg = curr_pkg;
 }
 
 
@@ -1246,7 +1249,7 @@ void inst_start(void)
 	active_frame_bbox = bbox_zero;
 	prev_pkgs = pkgs;
 	pkgs = NULL;
-	inst_select_pkg(NULL);
+	inst_select_pkg(NULL, 0);
 	curr_pkg = pkgs;
 	frame_instantiating = NULL;
 }
diff --git a/inst.h b/inst.h
index b64ed29..d79c930 100644
--- a/inst.h
+++ b/inst.h
@@ -134,6 +134,7 @@ extern struct inst *selected_inst;
 extern struct pkg *pkgs;	/* list of packages */
 extern struct pkg *active_pkg;	/* package selected in GUI */
 extern struct pkg *curr_pkg;	/* package currently being instantiated */
+extern struct pkg *reachable_pkg; /* package reachable with active vars */
 extern struct bbox active_frame_bbox;
 
 /*
@@ -195,7 +196,7 @@ void inst_begin_frame(struct obj *obj, struct frame *frame,
     struct coord base, int active, int is_active_frame);
 void inst_end_frame(const struct frame *frame);
 
-void inst_select_pkg(const char *name);
+void inst_select_pkg(const char *name, int active);
 
 struct bbox inst_get_bbox(void);
 
diff --git a/meas.c b/meas.c
index e505c68..234dea2 100644
--- a/meas.c
+++ b/meas.c
@@ -317,7 +317,7 @@ int instantiate_meas(int n_frames)
 	frame_instantiating = pkgs->insts[ip_frame];
 	for (pkg = pkgs; pkg; pkg = pkg->next)
 		if (pkg->name) {
-			inst_select_pkg(pkg->name);
+			inst_select_pkg(pkg->name, 0);
 			if (!instantiate_meas_pkg(n_frames))
 				return 0;
 			purge_meas(pkg);
diff --git a/obj.c b/obj.c
index ee2e73a..c4f8f14 100644
--- a/obj.c
+++ b/obj.c
@@ -1,8 +1,8 @@
 /*
  * obj.c - Object definition model
  *
- * Written 2009-2011 by Werner Almesberger
- * Copyright 2009-2011 by Werner Almesberger
+ * Written 2009-2012 by Werner Almesberger
+ * Copyright 2009-2012 by Werner Almesberger
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -336,7 +336,7 @@ static int generate_items(struct frame *frame, struct coord base, int active)
 	if (frame == frames) {
 		s = expand(pkg_name, frame);
 		/* s is NULL if expansion failed */
-		inst_select_pkg(s ? s : "_");
+		inst_select_pkg(s ? s : "_", active);
 		free(s);
 	}
 	inst_begin_active(active && frame == active_frame);