diff --git a/samples/propgrid/propgrid.cpp b/samples/propgrid/propgrid.cpp
index ceacdfaf40..9cc9bc7cbe 100644
--- a/samples/propgrid/propgrid.cpp
+++ b/samples/propgrid/propgrid.cpp
@@ -739,7 +739,7 @@ void FormMain::OnPropertyGridSelect( wxPropertyGridEvent& event )
     wxPGProperty* property = event.GetProperty();
     if ( property )
     {
-        m_itemEnable->Enable( TRUE );
+        m_itemEnable->Enable( true );
         if ( property->IsEnabled() )
             m_itemEnable->SetItemLabel( wxT("Disable") );
         else
@@ -747,7 +747,7 @@ void FormMain::OnPropertyGridSelect( wxPropertyGridEvent& event )
     }
     else
     {
-        m_itemEnable->Enable( FALSE );
+        m_itemEnable->Enable( false );
     }
 
 #if wxUSE_STATUSBAR
@@ -2029,7 +2029,7 @@ FormMain::FormMain(const wxString& title, const wxPoint& pos, const wxSize& size
     menuTools1->AppendSeparator();
     m_itemEnable = menuTools1->Append(ID_ENABLE, wxT("Enable"),
         wxT("Toggles item's enabled state.") );
-    m_itemEnable->Enable( FALSE );
+    m_itemEnable->Enable( false );
     menuTools1->Append(ID_HIDE, "Hide", "Hides a property" );
     menuTools1->Append(ID_SETREADONLY, "Set as Read-Only",
                        "Set property as read-only" );
@@ -2974,7 +2974,7 @@ void FormMain::OnMisc ( wxCommandEvent& event )
         wxVariant list;
         list.NullList();
         list.Append( wxVariant((long)1234,wxT("VariantLong")) );
-        list.Append( wxVariant((bool)TRUE,wxT("VariantBool")) );
+        list.Append( wxVariant(true,wxT("VariantBool")) );
         list.Append( wxVariant(wxT("Test Text"),wxT("VariantString")) );
         m_pPropGridManager->GetGrid()->SetPropertyValues(list);
     }
diff --git a/samples/propgrid/sampleprops.cpp b/samples/propgrid/sampleprops.cpp
index 1a696d0c88..ca5661179d 100644
--- a/samples/propgrid/sampleprops.cpp
+++ b/samples/propgrid/sampleprops.cpp
@@ -42,7 +42,7 @@
 // Dummy comparison required by value type implementation.
 bool operator == (const wxFontData&, const wxFontData&)
 {
-    return FALSE;
+    return false;
 }
 
 // Custom version of wxFontProperty that also holds colour in the value.
@@ -299,9 +299,9 @@ bool wxDirsProperty::OnCustomStringEdit( wxWindow* parent, wxString& value )
     if ( dlg.ShowModal() == wxID_OK )
     {
         value = dlg.GetPath();
-        return TRUE;
+        return true;
     }
-    return FALSE;
+    return false;
 }
 
 // -----------------------------------------------------------------------
@@ -384,22 +384,22 @@ bool wxArrayDoubleEditorDialog::ArrayInsert( const wxString& str, int index )
 {
     double d;
     if ( !str.ToDouble(&d) )
-        return FALSE;
+        return false;
 
     if (index<0)
         m_array.Add(d);
     else
         m_array.Insert(d,index);
-    return TRUE;
+    return true;
 }
 
 bool wxArrayDoubleEditorDialog::ArraySet( size_t index, const wxString& str )
 {
     double d;
     if ( !str.ToDouble(&d) )
-        return FALSE;
+        return false;
     m_array[index] = d;
-    return TRUE;
+    return true;
 }
 
 void wxArrayDoubleEditorDialog::ArrayRemoveAt( int index )
@@ -468,7 +468,7 @@ bool wxArrayDoubleEditorDialog::Create(wxWindow *parent,
 bool operator == (const wxArrayDouble& a, const wxArrayDouble& b)
 {
     if ( a.GetCount() != b.GetCount() )
-        return FALSE;
+        return false;
 
     size_t i;
 
@@ -478,10 +478,10 @@ bool operator == (const wxArrayDouble& a, const wxArrayDouble& b)
         if ( fabs(a[i] - b[i]) > 0.0000000001 )
         {
             //wxLogDebug(wxT("%f != %f"),a[i],b[i]);
-            return FALSE;
+            return false;
         }
     }
-    return TRUE;
+    return true;
 }
 
 WX_PG_IMPLEMENT_VARIANT_DATA_DUMMY_EQ(wxArrayDouble)
diff --git a/samples/propgrid/tests.cpp b/samples/propgrid/tests.cpp
index 54c27e2ace..acbcee9bef 100644
--- a/samples/propgrid/tests.cpp
+++ b/samples/propgrid/tests.cpp
@@ -626,7 +626,7 @@ bool FormMain::RunTests( bool fullTest, bool interactive )
         pgman->SetPropertyValue(wxT("StringProperty"),wxT("Text1"));
         pgman->SetPropertyValue(wxT("IntProperty"),1024);
         pgman->SetPropertyValue(wxT("FloatProperty"),1024.0000000001);
-        pgman->SetPropertyValue(wxT("BoolProperty"),FALSE);
+        pgman->SetPropertyValue(wxT("BoolProperty"),false);
         pgman->SetPropertyValue(wxT("EnumProperty"),120);
         pgman->SetPropertyValue(wxT("ArrayStringProperty"),test_arrstr_1);
         wxColour emptyCol;
@@ -648,7 +648,7 @@ bool FormMain::RunTests( bool fullTest, bool interactive )
             RT_FAILURE();
         if ( pg->GetPropertyValueAsDouble(wxT("FloatProperty")) != 1024.0000000001 )
             RT_FAILURE();
-        if ( pg->GetPropertyValueAsBool(wxT("BoolProperty")) != FALSE )
+        if ( pg->GetPropertyValueAsBool(wxT("BoolProperty")) != false )
             RT_FAILURE();
         if ( pg->GetPropertyValueAsLong(wxT("EnumProperty")) != 120 )
             RT_FAILURE();
@@ -678,7 +678,7 @@ bool FormMain::RunTests( bool fullTest, bool interactive )
         pg->SetPropertyValue(wxT("StringProperty"),wxT("Text2"));
         pg->SetPropertyValue(wxT("IntProperty"),512);
         pg->SetPropertyValue(wxT("FloatProperty"),512.0);
-        pg->SetPropertyValue(wxT("BoolProperty"),TRUE);
+        pg->SetPropertyValue(wxT("BoolProperty"),true);
         pg->SetPropertyValue(wxT("EnumProperty"),80);
         pg->SetPropertyValue(wxT("ArrayStringProperty"),test_arrstr_2);
         pg->SetPropertyValue(wxT("ColourProperty"),(wxObject*)wxWHITE);
@@ -699,7 +699,7 @@ bool FormMain::RunTests( bool fullTest, bool interactive )
             RT_FAILURE();
         if ( pgman->GetPropertyValueAsDouble(wxT("FloatProperty")) != 512.0 )
             RT_FAILURE();
-        if ( pgman->GetPropertyValueAsBool(wxT("BoolProperty")) != TRUE )
+        if ( pgman->GetPropertyValueAsBool(wxT("BoolProperty")) != true )
             RT_FAILURE();
         if ( pgman->GetPropertyValueAsLong(wxT("EnumProperty")) != 80 )
             RT_FAILURE();
@@ -1139,7 +1139,7 @@ bool FormMain::RunTests( bool fullTest, bool interactive )
     {
         RT_START_TEST(SetPropertyBackgroundColour)
         wxCommandEvent evt;
-        evt.SetInt(1); // IsChecked() will return TRUE.
+        evt.SetInt(1); // IsChecked() will return true.
         evt.SetId(ID_COLOURSCHEME4);
         OnCatColours(evt);
         OnColourScheme(evt);