diff --git a/gfxmenu/gui_box.c b/gfxmenu/gui_box.c
index 45028e5b1..38b15f96d 100644
--- a/gfxmenu/gui_box.c
+++ b/gfxmenu/gui_box.c
@@ -93,7 +93,7 @@ layout_horizontally (grub_gui_box_t self, int modify_layout,
 
   struct component_node *cur;
   unsigned w = 0, mwfrac = 0, h = 0, x = 0;
-  grub_fixed_unsigned_t wfrac = 0;
+  grub_fixed_signed_t wfrac = 0;
   int bogus_frac = 0;
 
   for (cur = self->chead.next; cur != &self->ctail; cur = cur->next)
@@ -104,17 +104,14 @@ layout_horizontally (grub_gui_box_t self, int modify_layout,
       if (c->ops->get_minimal_size)
 	c->ops->get_minimal_size (c, &mw, &mh);
 
-      if (!c->ishfrac && c->h > h)
+      if (c->h > (signed) h)
 	h = c->h;
       if (mh > h)
 	h = mh;
-      if (!c->iswfrac)
-	w += mw > c->w ? mw : c->w;
-      if (c->iswfrac)
-	{
-	  wfrac += c->wfrac;
-	  mwfrac += mw;
-	}
+      wfrac += c->wfrac;
+      w += c->w;
+      if (mw - c->w > 0)
+	mwfrac += mw - c->w;
     }
   if (wfrac > GRUB_FIXED_1 || (w > 0 && wfrac == GRUB_FIXED_1))
     bogus_frac = 1;
@@ -122,7 +119,7 @@ layout_horizontally (grub_gui_box_t self, int modify_layout,
   if (min_width)
     {
       if (wfrac < GRUB_FIXED_1)
-	*min_width = grub_fixed_ufu_divide (w, GRUB_FIXED_1 - wfrac);
+	*min_width = grub_fixed_sfs_divide (w, GRUB_FIXED_1 - wfrac);
       else
 	*min_width = w;
       if (*min_width < w + mwfrac)
@@ -142,16 +139,14 @@ layout_horizontally (grub_gui_box_t self, int modify_layout,
 
       r.x = x;
       r.y = 0;
-      r.width = 32;
       r.height = h;
 
       if (c->ops->get_minimal_size)
 	c->ops->get_minimal_size (c, &mw, &mh);
 
-      if (!c->iswfrac)
-	r.width = c->w;
-      if (c->iswfrac && !bogus_frac)
-	r.width = grub_fixed_ufu_multiply (self->bounds.width, c->wfrac);
+      r.width = c->w;
+      if (!bogus_frac)
+	r.width += grub_fixed_sfs_multiply (self->bounds.width, c->wfrac);
 
       if (r.width < mw)
 	r.width = mw;
@@ -171,7 +166,7 @@ layout_vertically (grub_gui_box_t self, int modify_layout,
 
   struct component_node *cur;
   unsigned h = 0, mhfrac = 0, w = 0, y = 0;
-  grub_fixed_unsigned_t hfrac = 0;
+  grub_fixed_signed_t hfrac = 0;
   int bogus_frac = 0;
 
   for (cur = self->chead.next; cur != &self->ctail; cur = cur->next)
@@ -182,17 +177,14 @@ layout_vertically (grub_gui_box_t self, int modify_layout,
       if (c->ops->get_minimal_size)
 	c->ops->get_minimal_size (c, &mw, &mh);
 
-      if (!c->iswfrac && c->w > w)
+      if (c->w > (signed) w)
 	w = c->w;
       if (mw > w)
 	w = mw;
-      if (!c->ishfrac)
-	h += mh > c->h ? mh : c->h;
-      if (c->ishfrac)
-	{
-	  hfrac += c->hfrac;
-	  mhfrac += mh;
-	}
+      hfrac += c->hfrac;
+      h += c->h;
+      if (mh - c->h > 0)
+	mhfrac += mh - c->h;
     }
   if (hfrac > GRUB_FIXED_1 || (h > 0 && hfrac == GRUB_FIXED_1))
     bogus_frac = 1;
@@ -200,7 +192,7 @@ layout_vertically (grub_gui_box_t self, int modify_layout,
   if (min_height)
     {
       if (hfrac < GRUB_FIXED_1)
-	*min_height = grub_fixed_ufu_divide (h, GRUB_FIXED_1 - hfrac);
+	*min_height = grub_fixed_sfs_divide (h, GRUB_FIXED_1 - hfrac);
       else
 	*min_height = h;
       if (*min_height < h + mhfrac)
@@ -221,15 +213,13 @@ layout_vertically (grub_gui_box_t self, int modify_layout,
       r.x = 0;
       r.y = y;
       r.width = w;
-      r.height = 32;
 
       if (c->ops->get_minimal_size)
 	c->ops->get_minimal_size (c, &mw, &mh);
 
-      if (!c->ishfrac)
-	r.height = c->h;
-      if (c->ishfrac)
-	r.height = grub_fixed_ufu_multiply (self->bounds.height, c->hfrac);
+      r.height = c->h;
+      if (!bogus_frac)
+	r.height += grub_fixed_sfs_multiply (self->bounds.height, c->hfrac);
 
       if (r.height < mh)
 	r.height = mh;
diff --git a/gfxmenu/gui_canvas.c b/gfxmenu/gui_canvas.c
index 8b55b2a73..b3919c2d3 100644
--- a/gfxmenu/gui_canvas.c
+++ b/gfxmenu/gui_canvas.c
@@ -88,49 +88,51 @@ canvas_paint (void *vself, const grub_video_rect_t *region)
     {
       grub_video_rect_t r;
       grub_gui_component_t comp;
+      signed x, y, w, h;
 
       comp = cur->component;
 
-      r.x = 0;
-      r.y = 0;
-      r.width = 32;
-      r.height = 32;
-
-      if (!comp->iswfrac && comp->w)
-	r.width = comp->w;
-
-      if (!comp->ishfrac && comp->h)
-	r.height = comp->h;
-
-      if (!comp->isxfrac && comp->x)
-	r.x = comp->x;
-
-      if (!comp->isyfrac && comp->y)
-	r.y = comp->y;
-
-      if (comp->ishfrac && comp->hfrac)
-	r.height = grub_fixed_ufu_multiply (self->bounds.height, comp->hfrac);
-
-      if (comp->iswfrac && comp->wfrac)
-	r.width = grub_fixed_ufu_multiply (self->bounds.width, comp->wfrac);
-
-      if (comp->isxfrac && comp->xfrac)
-	r.x = grub_fixed_ufu_multiply (self->bounds.width, comp->xfrac);
-
-      if (comp->isyfrac && comp->yfrac)
-	r.y = grub_fixed_ufu_multiply (self->bounds.height, comp->yfrac);
+      w = grub_fixed_sfs_multiply (self->bounds.width, comp->wfrac) + comp->w;
+      h = grub_fixed_sfs_multiply (self->bounds.height, comp->hfrac) + comp->h;
+      x = grub_fixed_sfs_multiply (self->bounds.width, comp->xfrac) + comp->x;
+      y = grub_fixed_sfs_multiply (self->bounds.height, comp->yfrac) + comp->y;
 
       if (comp->ops->get_minimal_size)
 	{
 	  unsigned mw;
 	  unsigned mh;
 	  comp->ops->get_minimal_size (comp, &mw, &mh);
-	  if (r.width < mw)
-	    r.width = mw;
-	  if (r.height < mh)
-	    r.height = mh;
+	  if (w < (signed) mw)
+	    w = mw;
+	  if (h < (signed) mh)
+	    h = mh;
 	}
 
+      /* Sanity checks.  */
+      if (w <= 0)
+	w = 32;
+      if (h <= 0)
+	h = 32;
+
+      if (x >= (signed) self->bounds.width)
+	x = self->bounds.width - 32;
+      if (y >= (signed) self->bounds.height)
+	y = self->bounds.height - 32;
+
+      if (x < 0)
+	x = 0;
+      if (y < 0)
+	y = 0;
+
+      if (x + w >= (signed) self->bounds.width)
+	w = self->bounds.width - x;
+      if (y + h >= (signed) self->bounds.height)
+	h = self->bounds.height - y;
+
+      r.x = x;
+      r.y = y;
+      r.width = w;
+      r.height = h;
       comp->ops->set_bounds (comp, &r);
 
       /* Paint the child.  */
diff --git a/gfxmenu/theme_loader.c b/gfxmenu/theme_loader.c
index 29bc1d2a6..09637d6b4 100644
--- a/gfxmenu/theme_loader.c
+++ b/gfxmenu/theme_loader.c
@@ -361,6 +361,40 @@ read_expression (struct parsebuf *p)
   return grub_new_substring (p->buf, start, end);
 }
 
+static grub_err_t
+parse_proportional_spec (char *value, signed *abs, grub_fixed_signed_t *prop)
+{
+  signed num;
+  char *ptr;
+  int sig = 0;
+  *abs = 0;
+  *prop = 0;
+  ptr = value;
+  while (*ptr)
+    {
+      sig = 0;
+
+      while (*ptr == '-' || *ptr == '+')
+	{
+	  if (*ptr == '-')
+	    sig = !sig;
+	  ptr++;
+	}
+
+      num = grub_strtoul (ptr, &ptr, 0);
+      if (grub_errno)
+	return grub_errno;
+      if (sig)
+	num = -num;
+      if (*ptr == '%')
+	*prop += grub_fixed_fsf_divide (grub_signed_to_fixed (num), 100);
+      else
+	*abs += num;
+    }
+  return GRUB_ERR_NONE;
+}
+
+
 /* Read a GUI object specification from the theme file.
    Any components created will be added to the GUI container PARENT.  */
 static grub_err_t
@@ -511,78 +545,16 @@ read_object (struct parsebuf *p, grub_gui_container_t parent)
 
       /* Handle the property value.  */
       if (grub_strcmp (property, "left") == 0)
-        {
-	  unsigned num;
-	  char *ptr;
-	  num = grub_strtoul (value, &ptr, 0);
-	  if (*ptr == '%')
-	    {
-	      component->isxfrac = 1;
-	      component->xfrac
-		= grub_fixed_fuf_divide (grub_unsigned_to_fixed (num), 100);
-	    }
-	  else
-	    {
-	      component->isxfrac = 0;
-	      component->x = num;
-	    }
-        }
+	parse_proportional_spec (value, &component->x, &component->xfrac);
       else if (grub_strcmp (property, "top") == 0)
-        {
-	  unsigned num;
-	  char *ptr;
-	  num = grub_strtoul (value, &ptr, 0);
-	  if (*ptr == '%')
-	    {
-	      component->isyfrac = 1;
-	      component->yfrac
-		= grub_fixed_fuf_divide (grub_unsigned_to_fixed (num), 100);
-	    }
-	  else
-	    {
-	      component->isyfrac = 0;
-	      component->y = num;
-	    }
-        }
+	parse_proportional_spec (value, &component->y, &component->yfrac);
       else if (grub_strcmp (property, "width") == 0)
-        {
-	  unsigned num;
-	  char *ptr;
-	  num = grub_strtoul (value, &ptr, 0);
-	  if (*ptr == '%')
-	    {
-	      component->iswfrac = 1;
-	      component->wfrac
-		= grub_fixed_fuf_divide (grub_unsigned_to_fixed (num), 100);
-	    }
-	  else
-	    {
-	      component->iswfrac = 0;
-	      component->w = num;
-	    }
-        }
+	parse_proportional_spec (value, &component->w, &component->wfrac);
       else if (grub_strcmp (property, "height") == 0)
-        {
-	  unsigned num;
-	  char *ptr;
-	  num = grub_strtoul (value, &ptr, 0);
-	  if (*ptr == '%')
-	    {
-	      component->ishfrac = 1;
-	      component->hfrac
-		= grub_fixed_fuf_divide (grub_unsigned_to_fixed (num), 100);
-	    }
-	  else
-	    {
-	      component->ishfrac = 0;
-	      component->h = num;
-	    }
-        }
+	parse_proportional_spec (value, &component->h, &component->hfrac);
       else
-        {
-          /* General property handling.  */
-          component->ops->set_property (component, property, value);
-        }
+	/* General property handling.  */
+	component->ops->set_property (component, property, value);
 
       grub_free (value);
       grub_free (property);
diff --git a/include/grub/gui.h b/include/grub/gui.h
index 873d29e76..7c4774838 100644
--- a/include/grub/gui.h
+++ b/include/grub/gui.h
@@ -75,62 +75,50 @@ struct grub_gui_list_ops
                          grub_gfxmenu_model_t menu);
 };
 
-typedef grub_uint32_t grub_fixed_unsigned_t;
+typedef signed grub_fixed_signed_t;
 #define GRUB_FIXED_1 0x10000
 
-static inline unsigned
-grub_fixed_ufu_divide (grub_uint32_t a, grub_fixed_unsigned_t b)
+static inline signed
+grub_fixed_sfs_divide (signed a, grub_fixed_signed_t b)
 {
-  return (a << 16) / b;
+  return (a * GRUB_FIXED_1) / b;
 }
 
-static inline grub_fixed_unsigned_t
-grub_fixed_fuf_divide (grub_fixed_unsigned_t a, grub_uint32_t b)
+static inline grub_fixed_signed_t
+grub_fixed_fsf_divide (grub_fixed_signed_t a, signed b)
 {
   return a / b;
 }
 
-static inline unsigned
-grub_fixed_ufu_multiply (grub_uint32_t a, grub_fixed_unsigned_t b)
+static inline signed
+grub_fixed_sfs_multiply (signed a, grub_fixed_signed_t b)
 {
-  return (a * b) >> 16;
+  return (a * b) / GRUB_FIXED_1;
 }
 
-static inline unsigned
-grub_fixed_to_unsigned (grub_fixed_unsigned_t in)
+static inline signed
+grub_fixed_to_signed (grub_fixed_signed_t in)
 {
-  return in >> 16;
+  return in / GRUB_FIXED_1;
 }
 
-static inline grub_fixed_unsigned_t
-grub_unsigned_to_fixed (unsigned in)
+static inline grub_fixed_signed_t
+grub_signed_to_fixed (signed in)
 {
-  return in << 16;
+  return in * GRUB_FIXED_1;
 }
 
 struct grub_gui_component
 {
   struct grub_gui_component_ops *ops;
-  int isxfrac:1;
-  int isyfrac:1;
-  int iswfrac:1;
-  int ishfrac:1;
-  union {
-    unsigned x;
-    grub_fixed_unsigned_t xfrac;
-  };
-  union {
-    unsigned y;
-    grub_fixed_unsigned_t yfrac;
-  };
-  union {
-    unsigned w;
-    grub_fixed_unsigned_t wfrac;
-  };
-  union {
-    unsigned h;
-    grub_fixed_unsigned_t hfrac;
-  };
+  signed x;
+  grub_fixed_signed_t xfrac;
+  signed y;
+  grub_fixed_signed_t yfrac;
+  signed w;
+  grub_fixed_signed_t wfrac;
+  signed h;
+  grub_fixed_signed_t hfrac;
 };
 
 struct grub_gui_container