diff --git a/src/GUI/Makefile.am b/src/GUI/Makefile.am
index 8cb594c55..7d6d59b82 100644
--- a/src/GUI/Makefile.am
+++ b/src/GUI/Makefile.am
@@ -8,6 +8,7 @@ endif
 
 libGUI_a_SOURCES = \
         new_gui.cxx new_gui.hxx \
+        dialog.cxx dialog.hxx \
 	menubar.cxx menubar.hxx \
 	gui.cxx gui.h gui_funcs.cxx \
 	gui_local.cxx gui_local.hxx \
diff --git a/src/GUI/dialog.cxx b/src/GUI/dialog.cxx
new file mode 100644
index 000000000..38c77697b
--- /dev/null
+++ b/src/GUI/dialog.cxx
@@ -0,0 +1,253 @@
+// dialog.cxx: implementation of an XML-configurable dialog box.
+
+#include <Input/input.hxx>
+
+#include "dialog.hxx"
+#include "new_gui.hxx"
+
+
+
+////////////////////////////////////////////////////////////////////////
+// Callbacks.
+////////////////////////////////////////////////////////////////////////
+
+/**
+ * Action callback.
+ */
+static void
+action_callback (puObject * object)
+{
+    GUIInfo * info = (GUIInfo *)object->getUserData();
+    NewGUI * gui =
+        (NewGUI *)globals->get_subsystem_mgr()
+          ->get_group(FGSubsystemMgr::INIT)->get_subsystem("gui");
+    gui->setCurrentWidget(info->widget);
+    for (int i = 0; i < info->bindings.size(); i++)
+        info->bindings[i]->fire();
+    gui->setCurrentWidget(0);
+}
+
+
+
+////////////////////////////////////////////////////////////////////////
+// Implementation of GUIInfo.
+////////////////////////////////////////////////////////////////////////
+
+GUIInfo::GUIInfo (FGDialog * w)
+    : widget(w)
+{
+}
+
+GUIInfo::~GUIInfo ()
+{
+    for (int i = 0; i < bindings.size(); i++) {
+        delete bindings[i];
+        bindings[i] = 0;
+    }
+}
+
+
+
+////////////////////////////////////////////////////////////////////////
+// Implementation of FGDialog.
+////////////////////////////////////////////////////////////////////////
+
+FGDialog::FGDialog (SGPropertyNode_ptr props)
+    : _object(0)
+{
+    display(props);
+}
+
+FGDialog::~FGDialog ()
+{
+    delete _object;
+
+    int i;
+    for (i = 0; i < _info.size(); i++) {
+        delete _info[i];
+        _info[i] = 0;
+    }
+
+    for (i = 0; i < _propertyObjects.size(); i++) {
+        delete _propertyObjects[i];
+        _propertyObjects[i] = 0;
+    }
+}
+
+void
+FGDialog::updateValue (const char * objectName)
+{
+    for (int i = 0; i < _propertyObjects.size(); i++) {
+        if (_propertyObjects[i]->name == objectName)
+            _propertyObjects[i]->object
+                ->setValue(_propertyObjects[i]->node->getStringValue());
+    }
+}
+
+void
+FGDialog::applyValue (const char * objectName)
+{
+    for (int i = 0; i < _propertyObjects.size(); i++) {
+        if (_propertyObjects[i]->name == objectName)
+            _propertyObjects[i]->node
+                ->setStringValue(_propertyObjects[i]
+                                 ->object->getStringValue());
+    }
+}
+
+void
+FGDialog::updateValues ()
+{
+    for (int i = 0; i < _propertyObjects.size(); i++) {
+        puObject * object = _propertyObjects[i]->object;
+        SGPropertyNode_ptr node = _propertyObjects[i]->node;
+        object->setValue(node->getStringValue());
+    }
+}
+
+void
+FGDialog::applyValues ()
+{
+    for (int i = 0; i < _propertyObjects.size(); i++) {
+        puObject * object = _propertyObjects[i]->object;
+        SGPropertyNode_ptr node = _propertyObjects[i]->node;
+        node->setStringValue(object->getStringValue());
+    }
+}
+
+void
+FGDialog::display (SGPropertyNode_ptr props)
+{
+    if (_object != 0) {
+        SG_LOG(SG_GENERAL, SG_ALERT, "This widget is already active");
+        return;
+    }
+
+    _object = makeObject(props, 1024, 768);
+
+    if (_object != 0) {
+        _object->reveal();
+    } else {
+        SG_LOG(SG_GENERAL, SG_ALERT, "Widget "
+               << props->getStringValue("name", "[unnamed]")
+               << " does not contain a proper GUI definition");
+    }
+}
+
+puObject *
+FGDialog::makeObject (SGPropertyNode * props, int parentWidth, int parentHeight)
+{
+    int width = props->getIntValue("width", parentWidth);
+    int height = props->getIntValue("height", parentHeight);
+
+    int x = props->getIntValue("x", (parentWidth - width) / 2);
+    int y = props->getIntValue("y", (parentHeight - height) / 2);
+
+    string type = props->getName();
+    if (type == "")
+        type = props->getStringValue("type");
+    if (type == "") {
+        SG_LOG(SG_GENERAL, SG_ALERT, "No type specified for GUI object");
+        return 0;
+    }
+
+    if (type == "dialog") {
+        puPopup * dialog;
+        if (props->getBoolValue("modal", false))
+            dialog = new puDialogBox(x, y);
+        else
+            dialog = new puPopup(x, y);
+        setupGroup(dialog, props, width, height, true);
+        return dialog;
+    } else if (type == "group") {
+        puGroup * group = new puGroup(x, y);
+        setupGroup(group, props, width, height, false);
+        return group;
+    } else if (type == "input") {
+        puInput * input = new puInput(x, y, x + width, y + height);
+        setupObject(input, props);
+        return input;
+    } else if (type == "text") {
+        puText * text = new puText(x, y);
+        setupObject(text, props);
+        return text;
+    } else if (type == "button") {
+        puButton * b;
+        const char * legend = props->getStringValue("legend", "[none]");
+        if (props->getBoolValue("one-shot", true))
+            b = new puOneShot(x, y, legend);
+        else
+            b = new puButton(x, y, legend);
+        setupObject(b, props);
+        return b;
+    } else {
+        return 0;
+    }
+}
+
+void
+FGDialog::setupObject (puObject * object, SGPropertyNode * props)
+{
+    if (props->hasValue("legend"))
+        object->setLegend(props->getStringValue("legend"));
+
+    if (props->hasValue("label"))
+        object->setLabel(props->getStringValue("label"));
+
+    if (props->hasValue("property")) {
+        const char * name = props->getStringValue("name");
+        if (name == 0)
+            name = "";
+        const char * propname = props->getStringValue("property");
+        SGPropertyNode_ptr node = fgGetNode(propname, true);
+        object->setValue(node->getStringValue());
+        if (name != 0)
+            _propertyObjects.push_back(new PropertyObject(name, object, node));
+    }
+
+    vector<SGPropertyNode_ptr> nodes = props->getChildren("binding");
+    if (nodes.size() > 0) {
+        GUIInfo * info = new GUIInfo(this);
+
+        for (int i = 0; i < nodes.size(); i++)
+            info->bindings.push_back(new FGBinding(nodes[i]));
+        object->setCallback(action_callback);
+        object->setUserData(info);
+        _info.push_back(info);
+    }
+
+    object->makeReturnDefault(props->getBoolValue("default"));
+}
+
+void
+FGDialog::setupGroup (puGroup * group, SGPropertyNode * props,
+                    int width, int height, bool makeFrame)
+{
+    setupObject(group, props);
+
+    if (makeFrame)
+        new puFrame(0, 0, width, height);
+
+    int nChildren = props->nChildren();
+    for (int i = 0; i < nChildren; i++)
+        makeObject(props->getChild(i), width, height);
+    group->close();
+}
+
+
+
+////////////////////////////////////////////////////////////////////////
+// Implementation of FGDialog::PropertyObject.
+////////////////////////////////////////////////////////////////////////
+
+FGDialog::PropertyObject::PropertyObject (const char * n,
+                                           puObject * o,
+                                           SGPropertyNode_ptr p)
+    : name(n),
+      object(o),
+      node(p)
+{
+}
+
+
+// end of dialog.cxx
diff --git a/src/GUI/dialog.hxx b/src/GUI/dialog.hxx
new file mode 100644
index 000000000..de2e900a9
--- /dev/null
+++ b/src/GUI/dialog.hxx
@@ -0,0 +1,116 @@
+// dialog.hxx - XML-configurable dialog box.
+
+#ifndef __DIALOG_HXX
+#define __DIALOG_HXX 1
+
+#ifndef __cplusplus
+# error This library requires C++
+#endif
+
+#include <plib/pu.h>
+
+#include <simgear/compiler.h>	// for SG_USING_STD
+#include <simgear/misc/props.hxx>
+
+#include <vector>
+SG_USING_STD(vector);
+
+class FGDialog;
+class FGBinding;
+
+
+/**
+ * PUI userdata describing a GUI object.
+ */
+struct GUIInfo
+{
+    GUIInfo (FGDialog * w);
+    virtual ~GUIInfo ();
+    
+    FGDialog * widget;
+    vector <FGBinding *> bindings;
+};
+
+
+/**
+ * Top-level GUI widget.
+ */
+class FGDialog
+{
+public:
+
+
+    /**
+     * Construct a new GUI widget configured by a property tree.
+     */
+    FGDialog (SGPropertyNode_ptr props);
+
+
+    /**
+     * Destructor.
+     */
+    virtual ~FGDialog ();
+
+
+    /**
+     * Update the values of all GUI objects with a specific name.
+     *
+     * This method copies from the property to the GUI object.
+     *
+     * @param objectName The name of the GUI object(s) to update.
+     *        Use the empty name for all unnamed objects.
+     */
+    virtual void updateValue (const char * objectName);
+
+
+    /**
+     * Apply the values of all GUI objects with a specific name.
+     *
+     * This method copies from the GUI object to the property.
+     *
+     * @param objectName The name of the GUI object(s) to update.
+     *        Use the empty name for all unnamed objects.
+     */
+    virtual void applyValue (const char * objectName);
+
+
+    /**
+     * Update the values of all GUI objects.
+     *
+     * This method copies from the properties to the GUI objects.
+     */
+    virtual void updateValues ();
+
+
+    /**
+     * Apply the values of all GUI objects.
+     *
+     * This method copies from the GUI objects to the properties.
+     */
+    virtual void applyValues ();
+
+
+private:
+    FGDialog (const FGDialog &); // just for safety
+
+    void display (SGPropertyNode_ptr props);
+    puObject * makeObject (SGPropertyNode * props,
+                           int parentWidth, int parentHeight);
+    void setupObject (puObject * object, SGPropertyNode * props);
+    void setupGroup (puGroup * group, SGPropertyNode * props,
+                     int width, int height, bool makeFrame = false);
+
+    puObject * _object;
+    vector<GUIInfo *> _info;
+    struct PropertyObject {
+        PropertyObject (const char * name,
+                        puObject * object,
+                        SGPropertyNode_ptr node);
+        string name;
+        puObject * object;
+        SGPropertyNode_ptr node;
+    };
+    vector<PropertyObject *> _propertyObjects;
+};
+
+#endif // __DIALOG_HXX
diff --git a/src/GUI/new_gui.cxx b/src/GUI/new_gui.cxx
index e7c6f939f..6be566c65 100644
--- a/src/GUI/new_gui.cxx
+++ b/src/GUI/new_gui.cxx
@@ -5,251 +5,11 @@
 #include <plib/pu.h>
 #include <plib/ul.h>
 
-#include <vector>
-SG_USING_STD(vector);
-
 #include <simgear/misc/exception.hxx>
 #include <Main/fg_props.hxx>
 
 #include "menubar.hxx"
-
-
-
-////////////////////////////////////////////////////////////////////////
-// Callbacks.
-////////////////////////////////////////////////////////////////////////
-
-/**
- * Action callback.
- */
-static void
-action_callback (puObject * object)
-{
-    GUIInfo * info = (GUIInfo *)object->getUserData();
-    NewGUI * gui =
-        (NewGUI *)globals->get_subsystem_mgr()
-          ->get_group(FGSubsystemMgr::INIT)->get_subsystem("gui");
-    gui->setCurrentWidget(info->widget);
-    for (int i = 0; i < info->bindings.size(); i++)
-        info->bindings[i]->fire();
-    gui->setCurrentWidget(0);
-}
-
-
-
-////////////////////////////////////////////////////////////////////////
-// Implementation of GUIInfo.
-////////////////////////////////////////////////////////////////////////
-
-GUIInfo::GUIInfo (GUIWidget * w)
-    : widget(w)
-{
-}
-
-GUIInfo::~GUIInfo ()
-{
-    for (int i = 0; i < bindings.size(); i++) {
-        delete bindings[i];
-        bindings[i] = 0;
-    }
-}
-
-
-
-////////////////////////////////////////////////////////////////////////
-// Implementation of GUIWidget.
-////////////////////////////////////////////////////////////////////////
-
-GUIWidget::GUIWidget (SGPropertyNode_ptr props)
-    : _object(0)
-{
-    display(props);
-}
-
-GUIWidget::~GUIWidget ()
-{
-    delete _object;
-
-    int i;
-    for (i = 0; i < _info.size(); i++) {
-        delete _info[i];
-        _info[i] = 0;
-    }
-
-    for (i = 0; i < _propertyObjects.size(); i++) {
-        delete _propertyObjects[i];
-        _propertyObjects[i] = 0;
-    }
-}
-
-void
-GUIWidget::updateValue (const char * objectName)
-{
-    for (int i = 0; i < _propertyObjects.size(); i++) {
-        if (_propertyObjects[i]->name == objectName)
-            _propertyObjects[i]->object
-                ->setValue(_propertyObjects[i]->node->getStringValue());
-    }
-}
-
-void
-GUIWidget::applyValue (const char * objectName)
-{
-    for (int i = 0; i < _propertyObjects.size(); i++) {
-        if (_propertyObjects[i]->name == objectName)
-            _propertyObjects[i]->node
-                ->setStringValue(_propertyObjects[i]
-                                 ->object->getStringValue());
-    }
-}
-
-void
-GUIWidget::updateValues ()
-{
-    for (int i = 0; i < _propertyObjects.size(); i++) {
-        puObject * object = _propertyObjects[i]->object;
-        SGPropertyNode_ptr node = _propertyObjects[i]->node;
-        object->setValue(node->getStringValue());
-    }
-}
-
-void
-GUIWidget::applyValues ()
-{
-    for (int i = 0; i < _propertyObjects.size(); i++) {
-        puObject * object = _propertyObjects[i]->object;
-        SGPropertyNode_ptr node = _propertyObjects[i]->node;
-        node->setStringValue(object->getStringValue());
-    }
-}
-
-void
-GUIWidget::display (SGPropertyNode_ptr props)
-{
-    if (_object != 0) {
-        SG_LOG(SG_GENERAL, SG_ALERT, "This widget is already active");
-        return;
-    }
-
-    _object = makeObject(props, 1024, 768);
-
-    if (_object != 0) {
-        _object->reveal();
-    } else {
-        SG_LOG(SG_GENERAL, SG_ALERT, "Widget "
-               << props->getStringValue("name", "[unnamed]")
-               << " does not contain a proper GUI definition");
-    }
-}
-
-puObject *
-GUIWidget::makeObject (SGPropertyNode * props, int parentWidth, int parentHeight)
-{
-    int width = props->getIntValue("width", parentWidth);
-    int height = props->getIntValue("height", parentHeight);
-
-    int x = props->getIntValue("x", (parentWidth - width) / 2);
-    int y = props->getIntValue("y", (parentHeight - height) / 2);
-
-    string type = props->getName();
-    if (type == "")
-        type = props->getStringValue("type");
-    if (type == "") {
-        SG_LOG(SG_GENERAL, SG_ALERT, "No type specified for GUI object");
-        return 0;
-    }
-
-    if (type == "dialog") {
-        puPopup * dialog;
-        if (props->getBoolValue("modal", false))
-            dialog = new puDialogBox(x, y);
-        else
-            dialog = new puPopup(x, y);
-        setupGroup(dialog, props, width, height, true);
-        return dialog;
-    } else if (type == "group") {
-        puGroup * group = new puGroup(x, y);
-        setupGroup(group, props, width, height, false);
-        return group;
-    } else if (type == "input") {
-        puInput * input = new puInput(x, y, x + width, y + height);
-        setupObject(input, props);
-        return input;
-    } else if (type == "text") {
-        puText * text = new puText(x, y);
-        setupObject(text, props);
-        return text;
-    } else if (type == "button") {
-        puButton * b;
-        const char * legend = props->getStringValue("legend", "[none]");
-        if (props->getBoolValue("one-shot", true))
-            b = new puOneShot(x, y, legend);
-        else
-            b = new puButton(x, y, legend);
-        setupObject(b, props);
-        return b;
-    } else {
-        return 0;
-    }
-}
-
-void
-GUIWidget::setupObject (puObject * object, SGPropertyNode * props)
-{
-    if (props->hasValue("legend"))
-        object->setLegend(props->getStringValue("legend"));
-
-    if (props->hasValue("label"))
-        object->setLabel(props->getStringValue("label"));
-
-    if (props->hasValue("property")) {
-        const char * name = props->getStringValue("name");
-        if (name == 0)
-            name = "";
-        const char * propname = props->getStringValue("property");
-        SGPropertyNode_ptr node = fgGetNode(propname, true);
-        object->setValue(node->getStringValue());
-        if (name != 0)
-            _propertyObjects.push_back(new PropertyObject(name, object, node));
-    }
-
-    vector<SGPropertyNode_ptr> nodes = props->getChildren("binding");
-    if (nodes.size() > 0) {
-        GUIInfo * info = new GUIInfo(this);
-
-        for (int i = 0; i < nodes.size(); i++)
-            info->bindings.push_back(new FGBinding(nodes[i]));
-        object->setCallback(action_callback);
-        object->setUserData(info);
-        _info.push_back(info);
-    }
-
-    object->makeReturnDefault(props->getBoolValue("default"));
-}
-
-void
-GUIWidget::setupGroup (puGroup * group, SGPropertyNode * props,
-                    int width, int height, bool makeFrame)
-{
-    setupObject(group, props);
-
-    if (makeFrame)
-        new puFrame(0, 0, width, height);
-
-    int nChildren = props->nChildren();
-    for (int i = 0; i < nChildren; i++)
-        makeObject(props->getChild(i), width, height);
-    group->close();
-}
-
-GUIWidget::PropertyObject::PropertyObject (const char * n,
-                                           puObject * o,
-                                           SGPropertyNode_ptr p)
-    : name(n),
-      object(o),
-      node(p)
-{
-}
+#include "dialog.hxx"
 
 
 
@@ -294,16 +54,16 @@ NewGUI::display (const string &name)
     if (_widgets.find(name) == _widgets.end())
         SG_LOG(SG_GENERAL, SG_ALERT, "Dialog " << name << " not defined");
     else
-        new GUIWidget(_widgets[name]);
+        new FGDialog(_widgets[name]);
 }
 
 void
-NewGUI::setCurrentWidget (GUIWidget * widget)
+NewGUI::setCurrentWidget (FGDialog * widget)
 {
     _current_widget = widget;
 }
 
-GUIWidget *
+FGDialog *
 NewGUI::getCurrentWidget ()
 {
     return _current_widget;
diff --git a/src/GUI/new_gui.hxx b/src/GUI/new_gui.hxx
index 6b5b0b9e0..4a7f425ce 100644
--- a/src/GUI/new_gui.hxx
+++ b/src/GUI/new_gui.hxx
@@ -20,105 +20,10 @@ SG_USING_STD(map);
 
 #include <Main/fgfs.hxx>
 #include <Main/fg_props.hxx>
-#include <Input/input.hxx>
 
 class FGMenuBar;
-class GUIWidget;
-
-
-/**
- * Information about a GUI widget.
- */
-struct GUIInfo
-{
-    GUIInfo (GUIWidget * w);
-    virtual ~GUIInfo ();
-
-    GUIWidget * widget;
-    vector <FGBinding *> bindings;
-};
-
-
-/**
- * Top-level GUI widget.
- */
-class GUIWidget
-{
-public:
-
-
-    /**
-     * Construct a new GUI widget configured by a property tree.
-     */
-    GUIWidget (SGPropertyNode_ptr props);
-
-
-    /**
-     * Destructor.
-     */
-    virtual ~GUIWidget ();
-
-
-    /**
-     * Update the values of all GUI objects with a specific name.
-     *
-     * This method copies from the property to the GUI object.
-     *
-     * @param objectName The name of the GUI object(s) to update.
-     *        Use the empty name for all unnamed objects.
-     */
-    virtual void updateValue (const char * objectName);
-
-
-    /**
-     * Apply the values of all GUI objects with a specific name.
-     *
-     * This method copies from the GUI object to the property.
-     *
-     * @param objectName The name of the GUI object(s) to update.
-     *        Use the empty name for all unnamed objects.
-     */
-    virtual void applyValue (const char * objectName);
-
-
-    /**
-     * Update the values of all GUI objects.
-     *
-     * This method copies from the properties to the GUI objects.
-     */
-    virtual void updateValues ();
-
-
-    /**
-     * Apply the values of all GUI objects.
-     *
-     * This method copies from the GUI objects to the properties.
-     */
-    virtual void applyValues ();
-
-
-private:
-    GUIWidget (const GUIWidget &); // just for safety
-
-    void display (SGPropertyNode_ptr props);
-    puObject * makeObject (SGPropertyNode * props,
-                           int parentWidth, int parentHeight);
-    void setupObject (puObject * object, SGPropertyNode * props);
-    void setupGroup (puGroup * group, SGPropertyNode * props,
-                     int width, int height, bool makeFrame = false);
-
-    puObject * _object;
-    vector<GUIInfo *> _info;
-    struct PropertyObject {
-        PropertyObject (const char * name,
-                        puObject * object,
-                        SGPropertyNode_ptr node);
-        string name;
-        puObject * object;
-        SGPropertyNode_ptr node;
-    };
-    vector<PropertyObject *> _propertyObjects;
-};
+class FGDialog;
+class FGBinding;
 
 
 class NewGUI : public FGSubsystem
@@ -131,8 +36,8 @@ public:
     virtual void update (double delta_time_sec);
     virtual void display (const string &name);
 
-    virtual void setCurrentWidget (GUIWidget * widget);
-    virtual GUIWidget * getCurrentWidget ();
+    virtual void setCurrentWidget (FGDialog * widget);
+    virtual FGDialog * getCurrentWidget ();
 
     virtual FGMenuBar * getMenuBar ();
 
@@ -142,7 +47,7 @@ private:
     void readDir (const char * path);
 
     FGMenuBar * _menubar;
-    GUIWidget * _current_widget;
+    FGDialog * _current_widget;
     map<string,SGPropertyNode_ptr> _widgets;
 
 };