diff --git a/panda/src/display/graphicsEngine.cxx b/panda/src/display/graphicsEngine.cxx
index d36ff3bc61..8b6487fe5d 100644
--- a/panda/src/display/graphicsEngine.cxx
+++ b/panda/src/display/graphicsEngine.cxx
@@ -267,6 +267,17 @@ remove_all_windows() {
   terminate_threads();
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: GraphicsEngine::is_empty
+//       Access: Published
+//  Description: Returns true if there are no windows managed by the
+//               engine, false if there is at least one.
+////////////////////////////////////////////////////////////////////
+bool GraphicsEngine::
+is_empty() const {
+  return _windows.empty();
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: GraphicsEngine::render_frame
 //       Access: Published
diff --git a/panda/src/display/graphicsEngine.h b/panda/src/display/graphicsEngine.h
index 2e778dd595..613eeccdfc 100644
--- a/panda/src/display/graphicsEngine.h
+++ b/panda/src/display/graphicsEngine.h
@@ -64,6 +64,7 @@ PUBLISHED:
                               const string &threading_model);
   bool remove_window(GraphicsWindow *window);
   void remove_all_windows();
+  bool is_empty() const;
 
   void render_frame();
   void sync_frame();
diff --git a/panda/src/egg/eggData.I b/panda/src/egg/eggData.I
index 28396fc4bb..8063d8a616 100644
--- a/panda/src/egg/eggData.I
+++ b/panda/src/egg/eggData.I
@@ -95,13 +95,13 @@ get_coordinate_system() const {
 ////////////////////////////////////////////////////////////////////
 //     Function: EggData::set_egg_filename
 //       Access: Public
-//  Description: Sets the directory in which the egg file is
-//               considered to reside.  This is also implicitly set by
-//               read().
+//  Description: Sets the filename--especially the directory part--in
+//               which the egg file is considered to reside.  This is
+//               also implicitly set by read().
 ////////////////////////////////////////////////////////////////////
 INLINE void EggData::
-set_egg_filename(const Filename &directory) {
-  _egg_filename = directory;
+set_egg_filename(const Filename &egg_filename) {
+  _egg_filename = egg_filename;
 }
 
 ////////////////////////////////////////////////////////////////////
diff --git a/panda/src/egg/eggData.h b/panda/src/egg/eggData.h
index af72b873a9..20bdd289e4 100644
--- a/panda/src/egg/eggData.h
+++ b/panda/src/egg/eggData.h
@@ -69,7 +69,7 @@ public:
   void set_coordinate_system(CoordinateSystem coordsys);
   INLINE CoordinateSystem get_coordinate_system() const;
 
-  INLINE void set_egg_filename(const Filename &directory);
+  INLINE void set_egg_filename(const Filename &egg_filenamea);
   INLINE const Filename &get_egg_filename() const;
 
   INLINE void recompute_vertex_normals(double threshold);
diff --git a/panda/src/event/eventParameter.I b/panda/src/event/eventParameter.I
index 176301cb3b..26da0d4756 100644
--- a/panda/src/event/eventParameter.I
+++ b/panda/src/event/eventParameter.I
@@ -37,9 +37,15 @@ EventParameter() {
 //  Description: Defines an EventParameter that stores a pointer to
 //               any kind of TypedReferenceCount object.  This is the
 //               most general constructor.
+//
+//               This accepts a const pointer, even though it stores
+//               (and eventually returns) a non-const pointer.  This
+//               is just the simplest way to allow both const and
+//               non-const pointers to be stored, but it does lose the
+//               constness.  Be careful.
 ////////////////////////////////////////////////////////////////////
 INLINE EventParameter::
-EventParameter(const TypedReferenceCount *ptr) : _ptr(ptr) { }
+EventParameter(const TypedReferenceCount *ptr) : _ptr((TypedReferenceCount *)ptr) { }
 
 
 ////////////////////////////////////////////////////////////////////
@@ -195,7 +201,7 @@ get_string_value() const {
 //               contains.  This is the only way to retrieve the value
 //               when it is not one of the above predefined types.
 ////////////////////////////////////////////////////////////////////
-INLINE const TypedReferenceCount *EventParameter::
+INLINE TypedReferenceCount *EventParameter::
 get_ptr() const {
   return _ptr;
 }
diff --git a/panda/src/event/eventParameter.h b/panda/src/event/eventParameter.h
index 9d0fce7f29..90a408431c 100644
--- a/panda/src/event/eventParameter.h
+++ b/panda/src/event/eventParameter.h
@@ -60,12 +60,12 @@ PUBLISHED:
   INLINE bool is_string() const;
   INLINE string get_string_value() const;
 
-  INLINE const TypedReferenceCount *get_ptr() const;
+  INLINE TypedReferenceCount *get_ptr() const;
 
   void output(ostream &out) const;
 
 private:
-  CPT(TypedReferenceCount) _ptr;
+  PT(TypedReferenceCount) _ptr;
 };
 
 INLINE ostream &operator << (ostream &out, const EventParameter &param);
diff --git a/panda/src/framework/pandaFramework.cxx b/panda/src/framework/pandaFramework.cxx
index dd73542997..1ffdecd7ce 100644
--- a/panda/src/framework/pandaFramework.cxx
+++ b/panda/src/framework/pandaFramework.cxx
@@ -205,6 +205,26 @@ open_window(const WindowProperties &props, GraphicsPipe *pipe) {
   return wf;
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: PandaFramework::find_window
+//       Access: Public
+//  Description: Returns the index of the WindowFramework object that
+//               references the indicated GraphicsWindow pointer, or
+//               -1 if none do.
+////////////////////////////////////////////////////////////////////
+int PandaFramework::
+find_window(const GraphicsWindow *win) const {
+  int n;
+  for (n = 0; n < (int)_windows.size(); n++) {
+    if (_windows[n]->get_graphics_window() == win) {
+      return n;
+    }
+  }
+
+  return -1;
+}
+
+
 ////////////////////////////////////////////////////////////////////
 //     Function: PandaFramework::close_window
 //       Access: Public
@@ -587,13 +607,28 @@ do_enable_default_keys() {
 ////////////////////////////////////////////////////////////////////
 //     Function: PandaFramework::event_esc
 //       Access: Protected, Static
-//  Description: Default handler for ESC or q key: exit the
-//               application.
+//  Description: Default handler for ESC or q key: close the current
+//               window (and exit the application if that was the last
+//               window).
 ////////////////////////////////////////////////////////////////////
 void PandaFramework::
-event_esc(CPT_Event, void *data) {
-  PandaFramework *self = (PandaFramework *)data;
-  self->_exit_flag = true;
+event_esc(CPT_Event event, void *data) { 
+  if (event->get_num_parameters() == 1) {
+    EventParameter param = event->get_parameter(0);
+    GraphicsWindow *win;
+    DCAST_INTO_V(win, param.get_ptr());
+
+    PandaFramework *self = (PandaFramework *)data;
+    int n = self->find_window(win);
+    if (n >= 0) {
+      self->close_window(n);
+    }
+
+    // If we closed the last window, shut down.
+    if (self->_windows.empty()) {
+      self->_exit_flag = true;
+    }
+  }
 }
 
 ////////////////////////////////////////////////////////////////////
@@ -661,18 +696,23 @@ event_l(CPT_Event, void *data) {
 //               the scene, or over the highlighted part of the scene.
 ////////////////////////////////////////////////////////////////////
 void PandaFramework::
-event_c(CPT_Event, void *data) {
-  PandaFramework *self = (PandaFramework *)data;
+event_c(CPT_Event event, void *data) {
+  if (event->get_num_parameters() == 1) {
+    EventParameter param = event->get_parameter(0);
+    const GraphicsWindow *win;
+    DCAST_INTO_V(win, param.get_ptr());
 
-  NodePath node = self->get_highlight();
-  if (node.is_empty()) {
-    node = self->get_models();
-  }
+    PandaFramework *self = (PandaFramework *)data;
 
-  Windows::iterator wi;
-  for (wi = self->_windows.begin(); wi != self->_windows.end(); ++wi) {
-    WindowFramework *wf = (*wi);
-    wf->center_trackball(node);
+    NodePath node = self->get_highlight();
+    if (node.is_empty()) {
+      node = self->get_models();
+    }
+
+    int n = self->find_window(win);
+    if (n >= 0) {
+      self->_windows[n]->center_trackball(node);
+    }
   }
 }
 
diff --git a/panda/src/framework/pandaFramework.h b/panda/src/framework/pandaFramework.h
index 3815faa37b..515dad5821 100644
--- a/panda/src/framework/pandaFramework.h
+++ b/panda/src/framework/pandaFramework.h
@@ -60,6 +60,7 @@ public:
 
   INLINE int get_num_windows() const;
   INLINE WindowFramework *get_window(int n) const;
+  int find_window(const GraphicsWindow *win) const;
   void close_window(int n);
   void close_all_windows();
   bool all_windows_closed() const;
diff --git a/panda/src/framework/windowFramework.cxx b/panda/src/framework/windowFramework.cxx
index 47450ec8a8..705989dafb 100644
--- a/panda/src/framework/windowFramework.cxx
+++ b/panda/src/framework/windowFramework.cxx
@@ -198,6 +198,7 @@ enable_keyboard() {
     NodePath mouse = get_mouse();
 
     PT(ButtonThrower) bt = new ButtonThrower("kb-events");
+    bt->add_parameter(EventParameter(_window));
     ModifierButtons mods;
     mods.add_button(KeyboardButton::shift());
     mods.add_button(KeyboardButton::control());
diff --git a/panda/src/tform/buttonThrower.cxx b/panda/src/tform/buttonThrower.cxx
index 8b27f0071a..35a502470e 100644
--- a/panda/src/tform/buttonThrower.cxx
+++ b/panda/src/tform/buttonThrower.cxx
@@ -22,6 +22,7 @@
 #include "buttonEventList.h"
 #include "dataNodeTransmit.h"
 #include "throw_event.h"
+#include "event.h"
 #include "indent.h"
 #include "dcast.h"
 
@@ -89,6 +90,44 @@ get_prefix() const {
   return _prefix;
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: ButtonThrower::add_parameter
+//       Access: Public
+//  Description: Adds the indicated parameter to the list of
+//               parameters that will be passed with each event
+//               generated by this ButtonThrower.
+////////////////////////////////////////////////////////////////////
+void ButtonThrower::
+add_parameter(const EventParameter &obj) {
+  _parameters.push_back(obj);
+}
+
+
+////////////////////////////////////////////////////////////////////
+//     Function: ButtonThrower::get_num_parameters
+//       Access: Public
+//  Description: Returns the number of parameters that have been added
+//               to the list of parameters to be passed with each
+//               event generated by this ButtonThrower.
+////////////////////////////////////////////////////////////////////
+int ButtonThrower::
+get_num_parameters() const {
+  return _parameters.size();
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: ButtonThrower::get_parameter
+//       Access: Public
+//  Description: Returns the nth parameter that has been added to the
+//               list of parameters passed with each event generated
+//               by this ButtonThrower.
+////////////////////////////////////////////////////////////////////
+EventParameter ButtonThrower::
+get_parameter(int n) const {
+  nassertr(n >= 0 && n < (int)_parameters.size(), EventParameter(0));
+  return _parameters[n];
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: ButtonThrower::get_modifier_buttons
 //       Access: Published
@@ -324,6 +363,24 @@ write(ostream &out, int indent_level) const {
   }    
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: ButtonThrower::do_throw_event
+//       Access: Private
+//  Description: Generates an event of the indicated name, adding on
+//               all of the user-requested parameters.
+////////////////////////////////////////////////////////////////////
+void ButtonThrower::
+do_throw_event(const string &event_name) {
+  Event *event = new Event(_prefix + event_name);
+
+  ParameterList::const_iterator pi;
+  for (pi = _parameters.begin(); pi != _parameters.end(); ++pi) {
+    event->add_parameter(*pi);
+  }
+
+  throw_event(event);
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: ButtonThrower::do_transmit_data
 //       Access: Protected, Virtual
@@ -362,7 +419,7 @@ do_transmit_data(const DataNodeTransmit &input, DataNodeTransmit &output) {
 
         if (!_throw_buttons_active || has_throw_button(_mods, be._button)) {
           // Process this button.
-          throw_event(_prefix + event_name);
+          do_throw_event(event_name);
           
         } else {
           // Don't process this button; instead, pass it down to future
@@ -385,7 +442,7 @@ do_transmit_data(const DataNodeTransmit &input, DataNodeTransmit &output) {
         // definition for the button at all, regardless of the state
         // of the modifier keys.
         if (!_throw_buttons_active || has_throw_button(be._button)) {
-          throw_event(_prefix + event_name + "-up");
+          do_throw_event(event_name + "-up");
         }
         if (_throw_buttons_active) {
           // Now pass the event on to future generations.  We always
diff --git a/panda/src/tform/buttonThrower.h b/panda/src/tform/buttonThrower.h
index fc9bb18d80..e6b504dd82 100644
--- a/panda/src/tform/buttonThrower.h
+++ b/panda/src/tform/buttonThrower.h
@@ -26,6 +26,7 @@
 #include "buttonEventList.h"
 #include "pvector.h"
 #include "pmap.h"
+#include "eventParameter.h"
 
 ////////////////////////////////////////////////////////////////////
 //       Class : ButtonThrower
@@ -48,6 +49,10 @@ PUBLISHED:
   bool has_prefix() const;
   string get_prefix() const;
 
+  void add_parameter(const EventParameter &obj);
+  int get_num_parameters() const;
+  EventParameter get_parameter(int n) const;
+
   const ModifierButtons &get_modifier_buttons() const;
   void set_modifier_buttons(const ModifierButtons &mods);
 
@@ -63,10 +68,16 @@ PUBLISHED:
 public:
   virtual void write(ostream &out, int indent_level = 0) const;
 
+private:
+  void do_throw_event(const string &event_name);
+
 private:
   string _prefix;
   ModifierButtons _mods;
 
+  typedef pvector<EventParameter> ParameterList;
+  ParameterList _parameters;
+
   typedef pvector<ModifierButtons> ThrowButtonDef;
   typedef pmap<ButtonHandle, ThrowButtonDef> ThrowButtons;
   ThrowButtons _throw_buttons;