diff --git a/src/gui/widgets/button-bar.cpp b/src/gui/widgets/button-bar.cpp
index f8b1e9904..8587410e7 100644
--- a/src/gui/widgets/button-bar.cpp
+++ b/src/gui/widgets/button-bar.cpp
@@ -23,15 +23,19 @@
 #include "button-bar.hpp"
 
 #include <nobug.h>
+#include <algorithm>
 
 using namespace Gtk;
+using namespace Glib;
 using namespace sigc;
+using namespace std;
 
 namespace gui {
 namespace widgets {
 
 ButtonBar::ButtonBar()
 {
+  set_flags(Gtk::NO_WINDOW);
 }
 
 void
@@ -40,5 +44,64 @@ ButtonBar::append(Widget &widget)
   pack_start(widget, Gtk::PACK_SHRINK);
 }
 
+void
+ButtonBar::on_size_request(Gtk::Requisition* requisition)
+{
+  REQUIRE(requisition);
+    
+  requisition->width = 0;
+  requisition->height = 0;
+  
+  Box::BoxList &list = children();
+  Box::BoxList::const_iterator i;
+  for(i = list.begin(); i != list.end(); i++)
+    {
+      Widget *widget = (*i).get_widget();
+      REQUIRE(widget);
+      
+      Requisition child_requisition = widget->size_request();
+      requisition->width += child_requisition.width;
+      requisition->height = max(requisition->height,
+        child_requisition.height);
+    }
+  
+  ENSURE(requisition->width >= 0);
+  ENSURE(requisition->height >= 0);
+}
+  
+void
+ButtonBar::on_size_allocate(Gtk::Allocation& allocation)
+{
+  //Use the offered allocation for this container:
+  set_allocation(allocation);
+  
+  int offset = 0;
+  Box::BoxList &list = children();
+  Box::BoxList::const_iterator i;
+  
+  for(i = list.begin(); i != list.end(); i++)
+    {
+      Widget *widget = (*i).get_widget();
+      REQUIRE(widget);
+     
+      const Requisition child_requisition = widget->size_request();
+      const Gtk::Allocation child_allocation(
+          allocation.get_x() + offset,
+          allocation.get_y(),
+          child_requisition.width,
+          allocation.get_height());
+          
+      offset += child_requisition.width;
+      
+      if(offset > allocation.get_width())
+        widget->set_child_visible(false);
+      else
+        {
+          widget->size_allocate(child_allocation);        
+          widget->set_child_visible(true);
+        }
+    }
+}
+
 } // widgets
 } // gui
diff --git a/src/gui/widgets/button-bar.hpp b/src/gui/widgets/button-bar.hpp
index dfa346467..d9a0b2d79 100644
--- a/src/gui/widgets/button-bar.hpp
+++ b/src/gui/widgets/button-bar.hpp
@@ -34,7 +34,7 @@ namespace widgets {
 /**
  * A modified toolbar widget for use in dialogs.
  **/
-class ButtonBar : public Gtk::HBox
+class ButtonBar : public Gtk::Box
 {
 public:
   /**
@@ -59,6 +59,23 @@ public:
     button.signal_clicked().connect(clicked_slot);
     append(button);
   }
+  
+private:
+  /* ===== Overrides ===== */
+
+  /**
+   * An event handler that is called to offer an allocation to this
+   * widget.
+   * @param requisition The area offered for this widget.
+   */
+  void on_size_request(Gtk::Requisition* requisition);
+  
+  /**
+   * An event handler that is called to notify this widget to allocate
+   * a given area for itself.
+   * @param allocation The area to allocate for this widget.
+   */
+  void on_size_allocate(Gtk::Allocation& allocation);
 };
 
 } // gui
diff --git a/src/gui/widgets/panel-bar.cpp b/src/gui/widgets/panel-bar.cpp
index 474579cdf..25e0a34d6 100644
--- a/src/gui/widgets/panel-bar.cpp
+++ b/src/gui/widgets/panel-bar.cpp
@@ -39,7 +39,7 @@ namespace gui {
 namespace widgets {
 
 PanelBar::PanelBar(panels::Panel &owner_panel, const gchar *stock_id) :
-  HBox(),
+  Box(),
   panel(owner_panel),
   panelButton(StockID(stock_id)),
   lockItem(NULL)
@@ -126,20 +126,66 @@ PanelBar::on_realize()
   unset_bg(STATE_NORMAL);
 }
 
+void
+PanelBar::on_size_request(Gtk::Requisition* requisition)
+{
+  REQUIRE(requisition);
+    
+  requisition->width = 0;
+  requisition->height = 0;
+  
+  Box::BoxList &list = children();
+  Box::BoxList::const_iterator i;
+  for(i = list.begin(); i != list.end(); i++)
+    {
+      Widget *widget = (*i).get_widget();
+      REQUIRE(widget);
+      
+      Requisition child_requisition = widget->size_request();
+      requisition->width += child_requisition.width;
+      requisition->height = max(requisition->height,
+        child_requisition.height);
+    }
+  
+  ENSURE(requisition->width >= 0);
+  ENSURE(requisition->height >= 0);
+}
+
 void
 PanelBar::on_size_allocate(Gtk::Allocation& allocation)
 {
+  // Use the offered allocation for this container
+  set_allocation(allocation);
+  
+  // Lay out the child widgets
+  int offset = 0;
+  Box::BoxList &list = children();
+  Box::BoxList::const_iterator i;
+  
+  for(i = list.begin(); i != list.end(); i++)
+    {
+      Widget *widget = (*i).get_widget();
+      REQUIRE(widget);
+     
+      const Requisition child_requisition = widget->size_request();
+      const Gtk::Allocation child_allocation(
+          offset, 0,
+          min(child_requisition.width, allocation.get_width() - offset),
+          allocation.get_height());
+          
+      offset += child_requisition.width;
+      
+      widget->size_allocate(child_allocation);
+    }
+  
+  // Resize the window
+  int width = allocation.get_width();
   if(window)
     {
-      const Requisition requisition(get_requisition());
-      const int width = max(min(requisition.width,
-        allocation.get_width()), 0);
+      width = max(min(allocation.get_width(), offset), 0);
       window->move_resize(allocation.get_x(), allocation.get_y(),
         width, allocation.get_height());
     }
-  
-  allocation.set_x(0);
-  HBox::on_size_allocate(allocation);
 }
 
 void
diff --git a/src/gui/widgets/panel-bar.hpp b/src/gui/widgets/panel-bar.hpp
index afccaa91c..30e08c91e 100644
--- a/src/gui/widgets/panel-bar.hpp
+++ b/src/gui/widgets/panel-bar.hpp
@@ -40,7 +40,7 @@ namespace widgets {
 /**
  * A container widget for widgets to be displayed on GDL panels grips.
  **/
-class PanelBar : public Gtk::HBox
+class PanelBar : public Gtk::Box
 {
 public:
 
@@ -66,6 +66,13 @@ private:
    **/
   void on_realize();
 
+  /**
+   * An event handler that is called to offer an allocation to this
+   * widget.
+   * @param requisition The area offered for this widget.
+   */
+  void on_size_request(Gtk::Requisition* requisition);
+
   /**
    * An override to intercept size allocate events.
    **/