diff --git a/pandatool/src/gtk-stats/gtkStatsChartMenu.cxx b/pandatool/src/gtk-stats/gtkStatsChartMenu.cxx
index c9fac65d89..8b695626ac 100755
--- a/pandatool/src/gtk-stats/gtkStatsChartMenu.cxx
+++ b/pandatool/src/gtk-stats/gtkStatsChartMenu.cxx
@@ -119,7 +119,7 @@ do_update() {
   for (int tc = 0; tc < num_toplevel_collectors; tc++) {
     int collector = client_data->get_toplevel_collector(tc);
     if (client_data->has_collector(collector) && 
-        client_data->get_collector_has_level(collector)) {
+        client_data->get_collector_has_level(collector, _thread_index)) {
 
       // We put a separator between the above frame collector and the
       // first level collector.
diff --git a/pandatool/src/gtk-stats/gtkStatsGraph.cxx b/pandatool/src/gtk-stats/gtkStatsGraph.cxx
index 36917672f2..c9e9f50ba1 100755
--- a/pandatool/src/gtk-stats/gtkStatsGraph.cxx
+++ b/pandatool/src/gtk-stats/gtkStatsGraph.cxx
@@ -42,9 +42,8 @@ const GdkColor GtkStatsGraph::rgb_user_guide_bar = {
 //  Description:
 ////////////////////////////////////////////////////////////////////
 GtkStatsGraph::
-GtkStatsGraph(GtkStatsMonitor *monitor, int thread_index) :
-  _monitor(monitor),
-  _thread_index(thread_index)
+GtkStatsGraph(GtkStatsMonitor *monitor) :
+  _monitor(monitor)
 {
   _parent_window = NULL;
   _window = NULL;
@@ -146,17 +145,6 @@ GtkStatsGraph::
   gtk_widget_destroy(_window);
 }
 
-////////////////////////////////////////////////////////////////////
-//     Function: GtkStatsGraph::get_thread_index
-//       Access: Public
-//  Description: Returns the thread index associated with this
-//               particular graph.
-////////////////////////////////////////////////////////////////////
-int GtkStatsGraph::
-get_thread_index() const {
-  return _thread_index;
-}
-
 ////////////////////////////////////////////////////////////////////
 //     Function: GtkStatsGraph::new_collector
 //       Access: Public, Virtual
diff --git a/pandatool/src/gtk-stats/gtkStatsGraph.h b/pandatool/src/gtk-stats/gtkStatsGraph.h
index 444bc74a0c..0e9f99a8c4 100755
--- a/pandatool/src/gtk-stats/gtkStatsGraph.h
+++ b/pandatool/src/gtk-stats/gtkStatsGraph.h
@@ -45,11 +45,9 @@ public:
   };
 
 public:
-  GtkStatsGraph(GtkStatsMonitor *monitor, int thread_index);
+  GtkStatsGraph(GtkStatsMonitor *monitor);
   virtual ~GtkStatsGraph();
 
-  int get_thread_index() const;
-
   virtual void new_collector(int collector_index);
   virtual void new_data(int thread_index, int frame_number);
   virtual void force_redraw();
@@ -81,7 +79,6 @@ protected:
   Brushes _brushes;
 
   GtkStatsMonitor *_monitor;
-  int _thread_index;
   GtkWidget *_parent_window;
   GtkWidget *_window;
   GtkWidget *_graph_window;
diff --git a/pandatool/src/gtk-stats/gtkStatsPianoRoll.cxx b/pandatool/src/gtk-stats/gtkStatsPianoRoll.cxx
index 4e78477c0b..1dcfa66d60 100644
--- a/pandatool/src/gtk-stats/gtkStatsPianoRoll.cxx
+++ b/pandatool/src/gtk-stats/gtkStatsPianoRoll.cxx
@@ -34,7 +34,7 @@ GtkStatsPianoRoll(GtkStatsMonitor *monitor, int thread_index) :
   PStatPianoRoll(monitor, thread_index, 
                  default_piano_roll_width,
                  default_piano_roll_height),
-  GtkStatsGraph(monitor, thread_index)
+  GtkStatsGraph(monitor)
 {
   // Let's show the units on the guide bar labels.  There's room.
   set_guide_bar_units(get_guide_bar_units() | GBU_show_units);
@@ -52,6 +52,12 @@ GtkStatsPianoRoll(GtkStatsMonitor *monitor, int thread_index) :
   gtk_widget_set_size_request(_graph_window, default_piano_roll_width,
 			      default_piano_roll_height);
 
+  const PStatClientData *client_data = 
+    GtkStatsGraph::_monitor->get_client_data();
+  string thread_name = client_data->get_thread_name(_thread_index);
+  string window_title = thread_name + " thread piano roll";
+  gtk_window_set_title(GTK_WINDOW(_window), window_title.c_str());
+      
   gtk_widget_show_all(_window);  
   gtk_widget_show(_window);
 
@@ -137,7 +143,7 @@ set_time_units(int unit_mask) {
 void GtkStatsPianoRoll::
 clicked_label(int collector_index) {
   if (collector_index >= 0) {
-    GtkStatsGraph::_monitor->open_strip_chart(GtkStatsGraph::_thread_index, collector_index, false);
+    GtkStatsGraph::_monitor->open_strip_chart(_thread_index, collector_index, false);
   }
 }
 
@@ -418,7 +424,7 @@ update_labels() {
   _label_stack.clear_labels();
   for (int i = 0; i < get_num_labels(); i++) {
     _label_stack.add_label(GtkStatsGraph::_monitor, this,
-			   GtkStatsGraph::_thread_index,
+			   _thread_index,
 			   get_label_collector(i), true);
   }
   _labels_changed = false;
diff --git a/pandatool/src/gtk-stats/gtkStatsStripChart.cxx b/pandatool/src/gtk-stats/gtkStatsStripChart.cxx
index 90d574511c..bff2cd35a1 100644
--- a/pandatool/src/gtk-stats/gtkStatsStripChart.cxx
+++ b/pandatool/src/gtk-stats/gtkStatsStripChart.cxx
@@ -34,10 +34,11 @@ GtkStatsStripChart(GtkStatsMonitor *monitor, int thread_index,
                    int collector_index, bool show_level) :
   PStatStripChart(monitor, 
                   show_level ? monitor->get_level_view(collector_index, thread_index) : monitor->get_view(thread_index), 
+                  thread_index,
                   collector_index, 
                   default_strip_chart_width,
                   default_strip_chart_height),
-  GtkStatsGraph(monitor, thread_index)
+  GtkStatsGraph(monitor)
 {
   _brush_origin = 0;
 
diff --git a/pandatool/src/pstatserver/pStatClientData.cxx b/pandatool/src/pstatserver/pStatClientData.cxx
index ea0d82cafd..48e8f3855b 100644
--- a/pandatool/src/pstatserver/pStatClientData.cxx
+++ b/pandatool/src/pstatserver/pStatClientData.cxx
@@ -161,21 +161,21 @@ get_collector_fullname(int index) const {
 //               otherwise.
 ////////////////////////////////////////////////////////////////////
 bool PStatClientData::
-set_collector_has_level(int index, bool flag) {
+set_collector_has_level(int index, int thread_index, bool flag) {
   bool any_changed = false;
   slot_collector(index);
   nassertr(index >= 0 && index < (int)_collectors.size(), false);
 
-  if (_collectors[index]._is_level != flag) {
+  if (_collectors[index]._is_level.get_bit(thread_index) != flag) {
     any_changed = true;
-    _collectors[index]._is_level = flag;
+    _collectors[index]._is_level.set_bit_to(thread_index, flag);
 
     // Turning this on for a given collector also implicitly turns all
     // of its ancestors.
     if (flag) {
       PStatCollectorDef *def = _collectors[index]._def;
       if (def->_parent_index != 0) {
-        set_collector_has_level(def->_parent_index, flag);
+        set_collector_has_level(def->_parent_index, thread_index, flag);
       }
     }
   }
@@ -192,9 +192,9 @@ set_collector_has_level(int index, bool flag) {
 //               Levels menu).
 ////////////////////////////////////////////////////////////////////
 bool PStatClientData::
-get_collector_has_level(int index) const {
+get_collector_has_level(int index, int thread_index) const {
   return (index >= 0 && index < (int)_collectors.size() &&
-          _collectors[index]._is_level);
+          _collectors[index]._is_level.get_bit(thread_index));
 }
 
 ////////////////////////////////////////////////////////////////////
@@ -327,8 +327,12 @@ add_collector(PStatCollectorDef *def) {
 
   // If we already had the _is_level flag set, it should be
   // immediately applied to all ancestors.
-  if (_collectors[def->_index]._is_level) {
-    set_collector_has_level(def->_parent_index, true);
+  const BitArray &is_level = _collectors[def->_index]._is_level;
+  int max_threads = is_level.get_num_bits();
+  for (int thread_index = 0; thread_index < max_threads; ++thread_index) {
+    if (is_level.get_bit(thread_index)) {
+      set_collector_has_level(def->_parent_index, thread_index, true);
+    }
   }
 }
 
@@ -391,7 +395,6 @@ slot_collector(int collector_index) {
   while ((int)_collectors.size() <= collector_index) {
     Collector collector;
     collector._def = (PStatCollectorDef *)NULL;
-    collector._is_level = false;
     _collectors.push_back(collector);
   }
 }
diff --git a/pandatool/src/pstatserver/pStatClientData.h b/pandatool/src/pstatserver/pStatClientData.h
index f9e0e04cef..d1b1f10fa3 100644
--- a/pandatool/src/pstatserver/pStatClientData.h
+++ b/pandatool/src/pstatserver/pStatClientData.h
@@ -26,6 +26,7 @@
 #include "pStatClientVersion.h"
 #include "referenceCount.h"
 #include "pointerTo.h"
+#include "bitArray.h"
 
 #include "pvector.h"
 #include "vector_int.h"
@@ -51,8 +52,8 @@ public:
   const PStatCollectorDef &get_collector_def(int index) const;
   string get_collector_name(int index) const;
   string get_collector_fullname(int index) const;
-  bool set_collector_has_level(int index, bool flag);
-  bool get_collector_has_level(int index) const;
+  bool set_collector_has_level(int index, int thread_index, bool flag);
+  bool get_collector_has_level(int index, int thread_index) const;
 
   int get_num_toplevel_collectors() const;
   int get_toplevel_collector(int index) const;
@@ -81,7 +82,7 @@ private:
   class Collector {
   public:
     PStatCollectorDef *_def;
-    bool _is_level;
+    BitArray _is_level;
   };
 
   typedef pvector<Collector> Collectors;
diff --git a/pandatool/src/pstatserver/pStatPianoRoll.h b/pandatool/src/pstatserver/pStatPianoRoll.h
index d713c630cb..217ec632fd 100644
--- a/pandatool/src/pstatserver/pStatPianoRoll.h
+++ b/pandatool/src/pstatserver/pStatPianoRoll.h
@@ -75,8 +75,10 @@ protected:
 private:
   void compute_page(const PStatFrameData &frame_data);
 
+protected:
   int _thread_index;
 
+private:
   float _time_width;
   float _start_time;
 
diff --git a/pandatool/src/pstatserver/pStatReader.cxx b/pandatool/src/pstatserver/pStatReader.cxx
index 217d6f655a..fe496cf187 100644
--- a/pandatool/src/pstatserver/pStatReader.cxx
+++ b/pandatool/src/pstatserver/pStatReader.cxx
@@ -314,10 +314,10 @@ dequeue_frame_data() {
     int num_levels = data._frame_data->get_num_levels();
     for (int i = 0; i < num_levels; i++) {
       int collector_index = data._frame_data->get_level_collector(i);
-      if (!_client_data->get_collector_has_level(collector_index)) {
+      if (!_client_data->get_collector_has_level(collector_index, data._thread_index)) {
         // This collector is now reporting level data, and it wasn't
         // before.
-        _client_data->set_collector_has_level(collector_index, true);
+        _client_data->set_collector_has_level(collector_index, data._thread_index, true);
         _monitor->new_collector(collector_index);
       }
     }
diff --git a/pandatool/src/pstatserver/pStatStripChart.cxx b/pandatool/src/pstatserver/pStatStripChart.cxx
index f735618937..ebd74dd7e3 100644
--- a/pandatool/src/pstatserver/pStatStripChart.cxx
+++ b/pandatool/src/pstatserver/pStatStripChart.cxx
@@ -34,8 +34,9 @@
 ////////////////////////////////////////////////////////////////////
 PStatStripChart::
 PStatStripChart(PStatMonitor *monitor, PStatView &view,
-                int collector_index, int xsize, int ysize) :
+                int thread_index, int collector_index, int xsize, int ysize) :
   PStatGraph(monitor, xsize, ysize),
+  _thread_index(thread_index),
   _view(view),
   _collector_index(collector_index)
 {
@@ -280,7 +281,6 @@ get_title_text() {
   string text;
 
   _title_unknown = false;
-  int _thread_index = 0;
 
   const PStatClientData *client_data = _monitor->get_client_data();
   if (client_data->has_collector(_collector_index)) {
@@ -299,7 +299,7 @@ get_title_text() {
 
   if (_thread_index != 0) {
     if (client_data->has_thread(_thread_index)) {
-      text += "(" + client_data->get_thread_name(_thread_index) + " thread)";
+      text += " (" + client_data->get_thread_name(_thread_index) + " thread)";
     } else {
       _title_unknown = true;
     }
diff --git a/pandatool/src/pstatserver/pStatStripChart.h b/pandatool/src/pstatserver/pStatStripChart.h
index 7e02a05ae9..327379341e 100644
--- a/pandatool/src/pstatserver/pStatStripChart.h
+++ b/pandatool/src/pstatserver/pStatStripChart.h
@@ -46,7 +46,7 @@ class PStatView;
 class PStatStripChart : public PStatGraph {
 public:
   PStatStripChart(PStatMonitor *monitor, PStatView &view,
-                  int collector_index, int xsize, int ysize);
+                  int thread_index, int collector_index, int xsize, int ysize);
   virtual ~PStatStripChart();
 
   void new_data(int frame_number);
@@ -124,6 +124,10 @@ private:
   void dec_label_usage(const FrameData &fdata);
   void inc_label_usage(const FrameData &fdata);
 
+protected:
+  int _thread_index;
+
+private:
   PStatView &_view;
   int _collector_index;
   bool _scroll_mode;
diff --git a/pandatool/src/text-stats/textMonitor.cxx b/pandatool/src/text-stats/textMonitor.cxx
index b8fa661499..374c32d9c8 100644
--- a/pandatool/src/text-stats/textMonitor.cxx
+++ b/pandatool/src/text-stats/textMonitor.cxx
@@ -113,7 +113,7 @@ new_data(int thread_index, int frame_number) {
       for (int tc = 0; tc < num_toplevel_collectors; tc++) {
         int collector = client_data->get_toplevel_collector(tc);
         if (client_data->has_collector(collector) && 
-            client_data->get_collector_has_level(collector)) {
+            client_data->get_collector_has_level(collector, thread_index)) {
           
           PStatView &level_view = get_level_view(collector, thread_index);
           level_view.set_to_frame(frame_number);
diff --git a/pandatool/src/win-stats/winStatsChartMenu.cxx b/pandatool/src/win-stats/winStatsChartMenu.cxx
index 7cfd50965a..c9c6d98f49 100755
--- a/pandatool/src/win-stats/winStatsChartMenu.cxx
+++ b/pandatool/src/win-stats/winStatsChartMenu.cxx
@@ -128,7 +128,7 @@ do_update() {
   for (int tc = 0; tc < num_toplevel_collectors; tc++) {
     int collector = client_data->get_toplevel_collector(tc);
     if (client_data->has_collector(collector) && 
-        client_data->get_collector_has_level(collector)) {
+        client_data->get_collector_has_level(collector, _thread_index)) {
 
       // We put a separator between the above frame collector and the
       // first level collector.
diff --git a/pandatool/src/win-stats/winStatsGraph.cxx b/pandatool/src/win-stats/winStatsGraph.cxx
index 3a15a845eb..45693b2263 100644
--- a/pandatool/src/win-stats/winStatsGraph.cxx
+++ b/pandatool/src/win-stats/winStatsGraph.cxx
@@ -32,9 +32,8 @@ WS_CHILD | WS_CLIPCHILDREN | WS_CLIPSIBLINGS | WS_OVERLAPPEDWINDOW | WS_VISIBLE;
 //  Description:
 ////////////////////////////////////////////////////////////////////
 WinStatsGraph::
-WinStatsGraph(WinStatsMonitor *monitor, int thread_index) :
-  _monitor(monitor),
-  _thread_index(thread_index)
+WinStatsGraph(WinStatsMonitor *monitor) :
+  _monitor(monitor)
 {
   _window = 0;
   _graph_window = 0;
@@ -93,17 +92,6 @@ WinStatsGraph::
   }
 }
 
-////////////////////////////////////////////////////////////////////
-//     Function: WinStatsGraph::get_thread_index
-//       Access: Public
-//  Description: Returns the thread index associated with this
-//               particular graph.
-////////////////////////////////////////////////////////////////////
-int WinStatsGraph::
-get_thread_index() const {
-  return _thread_index;
-}
-
 ////////////////////////////////////////////////////////////////////
 //     Function: WinStatsGraph::new_collector
 //       Access: Public, Virtual
diff --git a/pandatool/src/win-stats/winStatsGraph.h b/pandatool/src/win-stats/winStatsGraph.h
index da18054164..fae67a0d29 100644
--- a/pandatool/src/win-stats/winStatsGraph.h
+++ b/pandatool/src/win-stats/winStatsGraph.h
@@ -47,11 +47,9 @@ public:
   };
 
 public:
-  WinStatsGraph(WinStatsMonitor *monitor, int thread_index);
+  WinStatsGraph(WinStatsMonitor *monitor);
   virtual ~WinStatsGraph();
 
-  int get_thread_index() const;
-
   virtual void new_collector(int collector_index);
   virtual void new_data(int thread_index, int frame_number);
   virtual void force_redraw();
@@ -90,7 +88,6 @@ protected:
   Brushes _brushes;
 
   WinStatsMonitor *_monitor;
-  int _thread_index;
   HWND _window;
   HWND _graph_window;
   WinStatsLabelStack _label_stack;
diff --git a/pandatool/src/win-stats/winStatsPianoRoll.cxx b/pandatool/src/win-stats/winStatsPianoRoll.cxx
index 6408db63e5..c6f42914e3 100755
--- a/pandatool/src/win-stats/winStatsPianoRoll.cxx
+++ b/pandatool/src/win-stats/winStatsPianoRoll.cxx
@@ -36,7 +36,7 @@ WinStatsPianoRoll(WinStatsMonitor *monitor, int thread_index) :
   PStatPianoRoll(monitor, thread_index, 
                  default_piano_roll_width,
                  default_piano_roll_height),
-  WinStatsGraph(monitor, thread_index)
+  WinStatsGraph(monitor)
 {
   _left_margin = 128;
   _right_margin = 8;
@@ -127,7 +127,7 @@ set_time_units(int unit_mask) {
 void WinStatsPianoRoll::
 clicked_label(int collector_index) {
   if (collector_index >= 0) {
-    WinStatsGraph::_monitor->open_strip_chart(WinStatsGraph::_thread_index, collector_index, false);
+    WinStatsGraph::_monitor->open_strip_chart(_thread_index, collector_index, false);
   }
 }
 
@@ -467,7 +467,7 @@ update_labels() {
   for (int i = 0; i < get_num_labels(); i++) {
     int label_index = 
       _label_stack.add_label(WinStatsGraph::_monitor, this,
-                             WinStatsGraph::_thread_index,
+                             _thread_index,
                              get_label_collector(i), true);
   }
   _labels_changed = false;
@@ -562,7 +562,7 @@ create_window() {
 
   const PStatClientData *client_data = 
     WinStatsGraph::_monitor->get_client_data();
-  string thread_name = client_data->get_thread_name(WinStatsGraph::_thread_index);
+  string thread_name = client_data->get_thread_name(_thread_index);
   string window_title = thread_name + " thread piano roll";
 
 
diff --git a/pandatool/src/win-stats/winStatsStripChart.cxx b/pandatool/src/win-stats/winStatsStripChart.cxx
index 5523d5f953..4eb3d983e5 100644
--- a/pandatool/src/win-stats/winStatsStripChart.cxx
+++ b/pandatool/src/win-stats/winStatsStripChart.cxx
@@ -43,10 +43,11 @@ WinStatsStripChart(WinStatsMonitor *monitor, int thread_index,
                    int collector_index, bool show_level) :
   PStatStripChart(monitor, 
                   show_level ? monitor->get_level_view(collector_index, thread_index) : monitor->get_view(thread_index), 
+                  thread_index,
                   collector_index, 
                   default_strip_chart_width,
                   default_strip_chart_height),
-  WinStatsGraph(monitor, thread_index)
+  WinStatsGraph(monitor)
 {
   _brush_origin = 0;