diff --git a/panda/src/tform/mouseWatcherParameter.I b/panda/src/tform/mouseWatcherParameter.I
new file mode 100644
index 0000000000..e4da76ac42
--- /dev/null
+++ b/panda/src/tform/mouseWatcherParameter.I
@@ -0,0 +1,193 @@
+// Filename: mouseWatcherParameter.I
+// Created by:  drose (06Jul01)
+//
+////////////////////////////////////////////////////////////////////
+//
+// PANDA 3D SOFTWARE
+// Copyright (c) 2001, Disney Enterprises, Inc.  All rights reserved
+//
+// All use of this software is subject to the terms of the Panda 3d
+// Software license.  You should have received a copy of this license
+// along with this source code; you will also find a current copy of
+// the license at http://www.panda3d.org/license.txt .
+//
+// To contact the maintainers of this program write to
+// panda3d@yahoogroups.com .
+//
+////////////////////////////////////////////////////////////////////
+
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::Constructor
+//       Access: Public
+//  Description: 
+////////////////////////////////////////////////////////////////////
+INLINE MouseWatcherParameter::
+MouseWatcherParameter() {
+  _flags = 0;
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::Copy Constructor
+//       Access: Public
+//  Description: 
+////////////////////////////////////////////////////////////////////
+INLINE MouseWatcherParameter::
+MouseWatcherParameter(const MouseWatcherParameter &copy) :
+  _button(copy._button),
+  _mods(copy._mods),
+  _mouse(copy._mouse),
+  _flags(copy._flags)
+{
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::Copy Assignment Operator
+//       Access: Public
+//  Description: 
+////////////////////////////////////////////////////////////////////
+INLINE void MouseWatcherParameter::
+operator = (const MouseWatcherParameter &copy) {
+  _button = copy._button;
+  _mods = copy._mods;
+  _mouse = copy._mouse;
+  _flags = copy._flags;
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::Destructor
+//       Access: Public
+//  Description: 
+////////////////////////////////////////////////////////////////////
+INLINE MouseWatcherParameter::
+~MouseWatcherParameter() {
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::set_button
+//       Access: Public
+//  Description: Sets the mouse or keyboard button that generated this
+//               event, if any.
+////////////////////////////////////////////////////////////////////
+INLINE void MouseWatcherParameter::
+set_button(const ButtonHandle &button) {
+  _button = button;
+  _flags |= F_has_button;
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::set_modifier_buttons
+//       Access: Public
+//  Description: Sets the modifier buttons that were being held while
+//               this event was generated.
+////////////////////////////////////////////////////////////////////
+INLINE void MouseWatcherParameter::
+set_modifier_buttons(const ModifierButtons &mods) {
+  _mods = mods;
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::set_mouse
+//       Access: Public
+//  Description: Sets the mouse position that was current at the time
+//               the event was generated.
+////////////////////////////////////////////////////////////////////
+INLINE void MouseWatcherParameter::
+set_mouse(const LPoint2f &mouse) {
+  _mouse = mouse;
+  _flags |= F_has_mouse;
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::set_outside
+//       Access: Public
+//  Description: Sets the state of the "outside" flag.  This is true
+//               if the mouse was outside the region at the time the
+//               event was generated, false otherwise.  This only has
+//               meaning for "release" events.
+////////////////////////////////////////////////////////////////////
+INLINE void MouseWatcherParameter::
+set_outside(bool flag) {
+  if (flag) {
+    _flags |= F_is_outside;
+  } else {
+    _flags &= ~F_is_outside;
+  }
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::has_button
+//       Access: Published
+//  Description: Returns true if this parameter has an associated
+//               mouse or keyboard button, false otherwise.
+////////////////////////////////////////////////////////////////////
+INLINE bool MouseWatcherParameter::
+has_button() const {
+  return (_flags & F_has_button) != 0;
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::get_button
+//       Access: Published
+//  Description: Returns the mouse or keyboard button associated with
+//               this event.  It is valid to call this only if
+//               has_button(), above, returned true.
+////////////////////////////////////////////////////////////////////
+INLINE ButtonHandle MouseWatcherParameter::
+get_button() const {
+  nassertr(has_button(), ButtonHandle::none());
+  return _button;
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::get_modifier_buttons
+//       Access: Published
+//  Description: Returns the set of modifier buttons that were being
+//               held down while the event was generated.
+////////////////////////////////////////////////////////////////////
+INLINE const ModifierButtons &MouseWatcherParameter::
+get_modifier_buttons() const {
+  return _mods;
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::has_mouse
+//       Access: Published
+//  Description: Returns true if this parameter has an associated
+//               mouse position, false otherwise.
+////////////////////////////////////////////////////////////////////
+INLINE bool MouseWatcherParameter::
+has_mouse() const {
+  return (_flags & F_has_mouse) != 0;
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::get_mouse
+//       Access: Published
+//  Description: Returns the mouse position at the time the event was
+//               generated, in the normalized range (-1 .. 1).  It is
+//               valid to call this only if has_mouse() returned true.
+////////////////////////////////////////////////////////////////////
+INLINE const LPoint2f &MouseWatcherParameter::
+get_mouse() const {
+  nassertr(has_mouse(), _mouse);
+  return _mouse;
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::is_outside
+//       Access: Published
+//  Description: Returns true if the mouse was outside the region at
+//               the time the event was generated, false otherwise.
+//               This is only valid for "release" type events.
+////////////////////////////////////////////////////////////////////
+INLINE bool MouseWatcherParameter::
+is_outside() const {
+  return (_flags & F_is_outside) != 0;
+}
+
+INLINE ostream &
+operator << (ostream &out, const MouseWatcherParameter &parm) {
+  parm.output(out);
+  return out;
+}
diff --git a/panda/src/tform/mouseWatcherParameter.cxx b/panda/src/tform/mouseWatcherParameter.cxx
new file mode 100644
index 0000000000..ed442f3aff
--- /dev/null
+++ b/panda/src/tform/mouseWatcherParameter.cxx
@@ -0,0 +1,62 @@
+// Filename: mouseWatcherParameter.cxx
+// Created by:  drose (06Jul01)
+//
+////////////////////////////////////////////////////////////////////
+//
+// PANDA 3D SOFTWARE
+// Copyright (c) 2001, Disney Enterprises, Inc.  All rights reserved
+//
+// All use of this software is subject to the terms of the Panda 3d
+// Software license.  You should have received a copy of this license
+// along with this source code; you will also find a current copy of
+// the license at http://www.panda3d.org/license.txt .
+//
+// To contact the maintainers of this program write to
+// panda3d@yahoogroups.com .
+//
+////////////////////////////////////////////////////////////////////
+
+#include "mouseWatcherParameter.h"
+
+////////////////////////////////////////////////////////////////////
+//     Function: MouseWatcherParameter::output
+//       Access: Published
+//  Description: 
+////////////////////////////////////////////////////////////////////
+void MouseWatcherParameter::
+output(ostream &out) const {
+  bool output_anything = false;
+
+  if (has_button()) {
+    out << _button;
+    output_anything = true;
+  }
+
+  if (_mods.is_any_down()) {
+    if (output_anything) {
+      out << ", ";
+    }
+    out << _mods;
+    output_anything = true;
+  }
+
+  if (has_mouse()) {
+    if (output_anything) {
+      out << ", ";
+    }
+    out << "(" << _mouse << ")";
+    output_anything = true;
+  }
+
+  if (is_outside()) {
+    if (output_anything) {
+      out << ", ";
+    }
+    out << "outside";
+    output_anything = true;
+  }
+
+  if (!output_anything) {
+    out << "no parameters";
+  }
+}
diff --git a/panda/src/tform/mouseWatcherParameter.h b/panda/src/tform/mouseWatcherParameter.h
new file mode 100644
index 0000000000..ef75bc666f
--- /dev/null
+++ b/panda/src/tform/mouseWatcherParameter.h
@@ -0,0 +1,76 @@
+// Filename: mouseWatcherParameter.h
+// Created by:  drose (06Jul01)
+//
+////////////////////////////////////////////////////////////////////
+//
+// PANDA 3D SOFTWARE
+// Copyright (c) 2001, Disney Enterprises, Inc.  All rights reserved
+//
+// All use of this software is subject to the terms of the Panda 3d
+// Software license.  You should have received a copy of this license
+// along with this source code; you will also find a current copy of
+// the license at http://www.panda3d.org/license.txt .
+//
+// To contact the maintainers of this program write to
+// panda3d@yahoogroups.com .
+//
+////////////////////////////////////////////////////////////////////
+
+#ifndef MOUSEWATCHERPARAMETER_H
+#define MOUSEWATCHERPARAMETER_H
+
+#include "pandabase.h"
+
+#include "buttonHandle.h"
+#include "modifierButtons.h"
+#include "luse.h"
+
+////////////////////////////////////////////////////////////////////
+//       Class : MouseWatcherParameter
+// Description : This is sent along as a parameter to most events
+//               generated for a region to indicate the mouse and
+//               button state for the event.
+////////////////////////////////////////////////////////////////////
+class EXPCL_PANDA MouseWatcherParameter {
+public:
+  INLINE MouseWatcherParameter();
+  INLINE MouseWatcherParameter(const MouseWatcherParameter &other);
+  INLINE void operator = (const MouseWatcherParameter &other);
+  INLINE ~MouseWatcherParameter();
+
+  INLINE void set_button(const ButtonHandle &button);
+  INLINE void set_modifier_buttons(const ModifierButtons &mods);
+  INLINE void set_mouse(const LPoint2f &mouse);
+  INLINE void set_outside(bool flag);
+
+PUBLISHED:
+  INLINE bool has_button() const;
+  INLINE ButtonHandle get_button() const;
+
+  INLINE const ModifierButtons &get_modifier_buttons() const;
+
+  INLINE bool has_mouse() const;
+  INLINE const LPoint2f &get_mouse() const;
+
+  INLINE bool is_outside() const;
+
+  void output(ostream &out) const;
+
+public:
+  ButtonHandle _button;
+  ModifierButtons _mods;
+  LPoint2f _mouse;
+
+  enum Flags {
+    F_has_button  = 0x001,
+    F_has_mouse   = 0x002,
+    F_is_outside  = 0x004,
+  };
+  int _flags;
+};
+
+INLINE ostream &operator << (ostream &out, const MouseWatcherParameter &parm);
+
+#include "mouseWatcherParameter.I"
+
+#endif