diff --git a/panda/src/pgraphnodes/lightLensNode.cxx b/panda/src/pgraphnodes/lightLensNode.cxx
index 0aabcb07b4..cb84c28dfb 100644
--- a/panda/src/pgraphnodes/lightLensNode.cxx
+++ b/panda/src/pgraphnodes/lightLensNode.cxx
@@ -19,6 +19,7 @@
 #include "renderState.h"
 #include "cullFaceAttrib.h"
 #include "colorWriteAttrib.h"
+#include "lightAttrib.h"
 #include "graphicsStateGuardianBase.h"
 
 TypeHandle LightLensNode::_type_handle;
@@ -37,10 +38,14 @@ LightLensNode(const std::string &name, Lens *lens) :
   _shadow_caster = false;
   _sb_size.set(512, 512);
   _sb_sort = -10;
-  // set_initial_state(RenderState::make(ShaderAttrib::make_off(), 1000));
+
   // Backface culling helps eliminating artifacts.
-  set_initial_state(RenderState::make(CullFaceAttrib::make_reverse(),
-                    ColorWriteAttrib::make(ColorWriteAttrib::C_off)));
+  static CPT(RenderState) default_initial_state =
+    RenderState::make(
+      CullFaceAttrib::make_reverse(),
+      ColorWriteAttrib::make(ColorWriteAttrib::C_off)
+    )->set_attrib(LightAttrib::make_all_off(), RenderState::get_max_priority());
+  set_initial_state(default_initial_state);
 }
 
 /**
diff --git a/panda/src/putil/sparseArray.cxx b/panda/src/putil/sparseArray.cxx
index 450cc5a6b3..fdad9246a1 100644
--- a/panda/src/putil/sparseArray.cxx
+++ b/panda/src/putil/sparseArray.cxx
@@ -89,12 +89,16 @@ get_num_off_bits() const {
 
 /**
  * Returns the index of the lowest 1 bit in the array.  Returns -1 if there
- * are no 1 bits or if there are an infinite number of 1 bits.
+ * are no 1 bits and 0 if there are an infinite number of 1 bits.
  */
 int SparseArray::
 get_lowest_on_bit() const {
   if (_inverse) {
-    return -1;
+    if (_subranges.empty() || _subranges[0]._begin > 0) {
+      return 0;
+    } else {
+      return _subranges[0]._end;
+    }
   }
 
   if (_subranges.empty()) {
@@ -111,7 +115,11 @@ get_lowest_on_bit() const {
 int SparseArray::
 get_lowest_off_bit() const {
   if (!_inverse) {
-    return -1;
+    if (_subranges.empty() || _subranges[0]._begin > 0) {
+      return 0;
+    } else {
+      return _subranges[0]._end;
+    }
   }
 
   if (_subranges.empty()) {
diff --git a/panda/src/windisplay/winGraphicsWindow.cxx b/panda/src/windisplay/winGraphicsWindow.cxx
index 1f4e82be2a..4c111fad5c 100644
--- a/panda/src/windisplay/winGraphicsWindow.cxx
+++ b/panda/src/windisplay/winGraphicsWindow.cxx
@@ -1368,6 +1368,11 @@ adjust_z_order() {
 void WinGraphicsWindow::
 adjust_z_order(WindowProperties::ZOrder last_z_order,
                WindowProperties::ZOrder this_z_order) {
+  // Prevent calling this recursively.
+  if (_in_adjust_z_order) {
+    return;
+  }
+
   HWND order;
   bool do_change = false;
 
@@ -1397,8 +1402,10 @@ adjust_z_order(WindowProperties::ZOrder last_z_order,
     break;
   }
   if (do_change) {
+    _in_adjust_z_order = true;
     BOOL result = SetWindowPos(_hWnd, order, 0,0,0,0,
                                SWP_NOMOVE | SWP_NOSENDCHANGING | SWP_NOSIZE);
+    _in_adjust_z_order = false;
     if (!result) {
       windisplay_cat.warning()
         << "SetWindowPos failed.\n";
@@ -1690,7 +1697,9 @@ window_proc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam) {
     if (_hWnd != nullptr) {
       handle_reshape();
     }
-    adjust_z_order();
+    if (!_in_adjust_z_order) {
+      adjust_z_order();
+    }
     return 0;
 
   case WM_PAINT:
diff --git a/panda/src/windisplay/winGraphicsWindow.h b/panda/src/windisplay/winGraphicsWindow.h
index 9ce69d87a1..d0e8f938a2 100644
--- a/panda/src/windisplay/winGraphicsWindow.h
+++ b/panda/src/windisplay/winGraphicsWindow.h
@@ -199,6 +199,8 @@ private:
   UINT _num_touches;
   TOUCHINPUT _touches[MAX_TOUCHES];
 
+  bool _in_adjust_z_order = false;
+
 private:
   // We need this map to support per-window calls to window_proc().
   typedef std::map<HWND, WinGraphicsWindow *> WindowHandles;
diff --git a/tests/putil/test_sparsearray.py b/tests/putil/test_sparsearray.py
index 9721ad495a..adb7f2265c 100644
--- a/tests/putil/test_sparsearray.py
+++ b/tests/putil/test_sparsearray.py
@@ -251,6 +251,35 @@ def test_sparse_array_nonzero():
     assert sa
 
 
+def test_sparse_array_lowest_bit():
+    sa = core.SparseArray()
+    assert sa.get_lowest_off_bit() == 0
+    assert sa.get_lowest_on_bit() == -1
+
+    sa.invert_in_place()
+    assert sa.get_lowest_off_bit() == -1
+    assert sa.get_lowest_on_bit() == 0
+
+    sa = core.SparseArray()
+    sa.set_bit(0)
+    sa.set_bit(1)
+    assert sa.get_lowest_off_bit() == 2
+    assert sa.get_lowest_on_bit() == 0
+
+    sa.invert_in_place()
+    assert sa.get_lowest_off_bit() == 0
+    assert sa.get_lowest_on_bit() == 2
+
+    sa = core.SparseArray()
+    sa.set_bit(2)
+    assert sa.get_lowest_off_bit() == 0
+    assert sa.get_lowest_on_bit() == 2
+
+    sa.invert_in_place()
+    assert sa.get_lowest_off_bit() == 2
+    assert sa.get_lowest_on_bit() == 0
+
+
 def test_sparse_array_getstate():
     sa = core.SparseArray()
     assert sa.__getstate__() == ()