diff --git a/common/lset.cpp b/common/lset.cpp
index 0c3ebd6b0d..98c1a45919 100644
--- a/common/lset.cpp
+++ b/common/lset.cpp
@@ -544,23 +544,23 @@ PCB_LAYER_ID LSET::ExtractLayer() const
 }
 
 
-LSET LSET::FrontAssembly()
+const LSET& LSET::FrontAssembly()
 {
-    static const LSET saved( { F_SilkS, F_Mask, F_Fab, F_CrtYd } );
+    static LSET saved( { F_SilkS, F_Mask, F_Fab, F_CrtYd } );
     return saved;
 }
 
 
-LSET LSET::BackAssembly()
+const LSET& LSET::BackAssembly()
 {
-    static const LSET saved( { B_SilkS, B_Mask, B_Fab, B_CrtYd } );
+    static LSET saved( { B_SilkS, B_Mask, B_Fab, B_CrtYd } );
     return saved;
 }
 
 
-LSET LSET::InternalCuMask()
+const LSET& LSET::InternalCuMask()
 {
-    static const LSET saved( { In1_Cu,  In2_Cu,  In3_Cu,  In4_Cu,  In5_Cu,  In6_Cu,
+    static LSET saved( { In1_Cu,  In2_Cu,  In3_Cu,  In4_Cu,  In5_Cu,  In6_Cu,
                                In7_Cu,  In8_Cu,  In9_Cu,  In10_Cu, In11_Cu, In12_Cu,
                                In13_Cu, In14_Cu, In15_Cu, In16_Cu, In17_Cu, In18_Cu,
                                In19_Cu, In20_Cu, In21_Cu, In22_Cu, In23_Cu, In24_Cu,
@@ -591,73 +591,72 @@ LSET LSET::AllNonCuMask()
 }
 
 
-LSET LSET::ExternalCuMask()
+const LSET& LSET::ExternalCuMask()
 {
-    static const LSET saved( { F_Cu, B_Cu } );
+    static LSET saved( { F_Cu, B_Cu } );
     return saved;
 }
 
 
-LSET LSET::AllLayersMask()
+const LSET& LSET::AllLayersMask()
 {
-    static const LSET saved = LSET().set();
+    static LSET saved = LSET().set();
     return saved;
 }
 
 
-LSET LSET::BackTechMask()
+const LSET& LSET::BackTechMask()
 {
-    static const LSET saved( { B_SilkS, B_Mask, B_Adhes, B_Paste, B_CrtYd, B_Fab } );
+    static LSET saved( { B_SilkS, B_Mask, B_Adhes, B_Paste, B_CrtYd, B_Fab } );
     return saved;
 }
 
 
-LSET LSET::BackBoardTechMask()
+const LSET& LSET::BackBoardTechMask()
 {
-    static const LSET saved( { B_SilkS, B_Mask, B_Adhes, B_Paste } );
+    static LSET saved( { B_SilkS, B_Mask, B_Adhes, B_Paste } );
     return saved;
 }
 
 
-LSET LSET::FrontTechMask()
+const LSET& LSET::FrontTechMask()
 {
-    static const LSET saved( { F_SilkS, F_Mask, F_Adhes, F_Paste, F_CrtYd, F_Fab } );
+    static LSET saved( { F_SilkS, F_Mask, F_Adhes, F_Paste, F_CrtYd, F_Fab } );
     return saved;
 }
 
 
-LSET LSET::FrontBoardTechMask()
+const LSET& LSET::FrontBoardTechMask()
 {
-    static const LSET saved( { F_SilkS, F_Mask, F_Adhes, F_Paste } );
+    static LSET saved( { F_SilkS, F_Mask, F_Adhes, F_Paste } );
     return saved;
 }
 
 
-LSET LSET::AllTechMask()
+const LSET& LSET::AllTechMask()
 {
-    static const LSET saved = BackTechMask() | FrontTechMask();
+    static LSET saved = BackTechMask() | FrontTechMask();
     return saved;
 }
 
 
-LSET LSET::AllBoardTechMask()
+const LSET& LSET::AllBoardTechMask()
 {
-    static const LSET saved = BackBoardTechMask() | FrontBoardTechMask();
+    static LSET saved = BackBoardTechMask() | FrontBoardTechMask();
     return saved;
 }
 
 
-LSET LSET::UserMask()
+const LSET& LSET::UserMask()
 {
-    static const LSET saved( { Dwgs_User, Cmts_User, Eco1_User, Eco2_User, Edge_Cuts, Margin } );
-
+    static LSET saved( { Dwgs_User, Cmts_User, Eco1_User, Eco2_User, Edge_Cuts, Margin } );
     return saved;
 }
 
 
-LSET LSET::PhysicalLayersMask()
+const LSET& LSET::PhysicalLayersMask()
 {
-    static const LSET saved = AllBoardTechMask() | AllCuMask();
+    static LSET saved = AllBoardTechMask() | AllCuMask();
     return saved;
 }
 
@@ -680,31 +679,30 @@ LSET LSET::UserDefinedLayersMask( int aUserDefinedLayerCount )
 }
 
 
-LSET LSET::FrontMask()
+const LSET& LSET::FrontMask()
 {
-    static const LSET saved = FrontTechMask().set( F_Cu );
+    static LSET saved = LSET( FrontTechMask() ).set( F_Cu );
     return saved;
 }
 
 
-LSET LSET::BackMask()
+const LSET& LSET::BackMask()
 {
-    static const LSET saved = BackTechMask().set( B_Cu );
+    static LSET saved = LSET( BackTechMask() ).set( B_Cu );
     return saved;
 }
 
 
-LSET LSET::SideSpecificMask()
+const LSET& LSET::SideSpecificMask()
 {
-    static const LSET saved = BackTechMask() | FrontTechMask() | AllCuMask();
+    static LSET saved = BackTechMask() | FrontTechMask() | AllCuMask();
     return saved;
 }
 
 
-LSET LSET::ForbiddenFootprintLayers()
+const LSET& LSET::ForbiddenFootprintLayers()
 {
-    static LSET saved = InternalCuMask();
-    saved.set( In1_Cu, false );
+    static LSET saved = LSET( InternalCuMask() ).set( In1_Cu, false );
     return saved;
 }
 
diff --git a/include/board_design_settings.h b/include/board_design_settings.h
index fdd515d0a7..e290f3b16f 100644
--- a/include/board_design_settings.h
+++ b/include/board_design_settings.h
@@ -571,7 +571,7 @@ public:
      *
      * @return the enabled layers in bit-mapped form.
      */
-    inline LSET GetEnabledLayers() const
+    inline const LSET& GetEnabledLayers() const
     {
         return m_enabledLayers;
     }
diff --git a/include/lset.h b/include/lset.h
index af2fc8284e..4ab472b80c 100644
--- a/include/lset.h
+++ b/include/lset.h
@@ -102,17 +102,17 @@ public:
      * Return a complete set of internal copper layers which is all Cu layers
      * except #F_Cu and #B_Cu.
      */
-    static LSET InternalCuMask();
+    static const LSET& InternalCuMask();
 
     /**
      * Return a complete set of all top assembly layers which is all #F_SilkS and #F_Mask.
      */
-    static LSET FrontAssembly();
+    static const LSET& FrontAssembly();
 
     /**
      * Return a complete set of all bottom assembly layers which is all #B_SilkS and #B_Mask.
      */
-    static LSET BackAssembly();
+    static const LSET& BackAssembly();
 
     /**
      * Return a mask holding the requested number of Cu PCB_LAYER_IDs.
@@ -122,67 +122,67 @@ public:
     /**
      * Return a mask holding the Front and Bottom layers.
      */
-    static LSET ExternalCuMask();
+    static const LSET& ExternalCuMask();
 
     /**
      * Return a mask holding all layer minus CU layers.
      */
     static LSET AllNonCuMask();
 
-    static LSET AllLayersMask();
+    static const LSET& AllLayersMask();
 
     /**
      * Return a mask holding all technical layers (no CU layer) on front side.
      */
-    static LSET FrontTechMask();
+    static const LSET& FrontTechMask();
 
     /**
      * Return a mask holding technical layers used in a board fabrication
      * (no CU layer) on front side.
      */
-    static LSET FrontBoardTechMask();
+    static const LSET& FrontBoardTechMask();
 
     /**
      * Return a mask holding all technical layers (no CU layer) on back side.
      */
-    static LSET BackTechMask();
+    static const LSET& BackTechMask();
 
     /**
      * Return a mask holding technical layers used in a board fabrication
      * (no CU layer) on Back side.
      */
-    static LSET BackBoardTechMask();
+    static const LSET& BackBoardTechMask();
 
     /**
      * Return a mask holding all technical layers (no CU layer) on both side.
      */
-    static LSET AllTechMask();
+    static const LSET& AllTechMask();
 
     /**
      * Return a mask holding board technical layers (no CU layer) on both side.
      */
-    static LSET AllBoardTechMask();
+    static const LSET& AllBoardTechMask();
 
     /**
      * Return a mask holding all technical layers and the external CU layer on front side.
      */
-    static LSET FrontMask();
+    static const LSET& FrontMask();
 
     /**
      * Return a mask holding all technical layers and the external CU layer on back side.
      */
-    static LSET BackMask();
+    static const LSET& BackMask();
 
-    static LSET SideSpecificMask();
+    static const LSET& SideSpecificMask();
 
-    static LSET UserMask();
+    static const LSET& UserMask();
 
     /**
      * Return a mask holding all layers which are physically realized.
      *
      * Equivalent to the copper layers + the board tech mask.
      */
-    static LSET PhysicalLayersMask();
+    static const LSET& PhysicalLayersMask();
 
     /**
      * Return a mask with the requested number of user defined layers.
@@ -197,7 +197,7 @@ public:
      * Currently internal copper layers and Margin.
      */
 
-    static LSET ForbiddenFootprintLayers();
+    static const LSET& ForbiddenFootprintLayers();
 
     /**
      * Return a sequence of copper layers in starting from the front/top
diff --git a/pcbnew/board.cpp b/pcbnew/board.cpp
index 25f6efdfbb..30e40f1e02 100644
--- a/pcbnew/board.cpp
+++ b/pcbnew/board.cpp
@@ -828,7 +828,7 @@ int BOARD::LayerDepth( PCB_LAYER_ID aStartLayer, PCB_LAYER_ID aEndLayer ) const
 }
 
 
-LSET BOARD::GetEnabledLayers() const
+const LSET& BOARD::GetEnabledLayers() const
 {
     return GetDesignSettings().GetEnabledLayers();
 }
@@ -842,7 +842,7 @@ bool BOARD::IsLayerVisible( PCB_LAYER_ID aLayer ) const
 }
 
 
-LSET BOARD::GetVisibleLayers() const
+const LSET& BOARD::GetVisibleLayers() const
 {
     return m_project ? m_project->GetLocalSettings().m_VisibleLayers : LSET::AllLayersMask();
 }
diff --git a/pcbnew/board.h b/pcbnew/board.h
index 472cd37092..f3e7cca22b 100644
--- a/pcbnew/board.h
+++ b/pcbnew/board.h
@@ -607,7 +607,7 @@ public:
      *
      * @return the enabled layers in bit-mapped form.
      */
-    LSET GetEnabledLayers() const;
+    const LSET& GetEnabledLayers() const;
     LSET GetLayerSet() const override { return GetEnabledLayers(); }
 
     /**
@@ -640,7 +640,7 @@ public:
      *
      * @return the visible layers in bit-mapped form.
      */
-    LSET  GetVisibleLayers() const;
+    const LSET& GetVisibleLayers() const;
 
     /**
      * A proxy function that calls the correspondent function in m_BoardSettings
diff --git a/pcbnew/drc/drc_test_provider_misc.cpp b/pcbnew/drc/drc_test_provider_misc.cpp
index 803bd802a9..eb705498bd 100644
--- a/pcbnew/drc/drc_test_provider_misc.cpp
+++ b/pcbnew/drc/drc_test_provider_misc.cpp
@@ -168,7 +168,7 @@ void DRC_TEST_PROVIDER_MISC::testDisabledLayers()
                 return true;
             };
 
-    LSET disabledLayers = m_board->GetEnabledLayers().flip();
+    LSET disabledLayers = LSET( m_board->GetEnabledLayers() ).flip();
 
     // Perform the test only for copper layers
     disabledLayers &= LSET::AllCuMask();
diff --git a/pcbnew/drc/drc_test_provider_physical_clearance.cpp b/pcbnew/drc/drc_test_provider_physical_clearance.cpp
index 8fc2a16dca..f6417fc7f9 100644
--- a/pcbnew/drc/drc_test_provider_physical_clearance.cpp
+++ b/pcbnew/drc/drc_test_provider_physical_clearance.cpp
@@ -148,10 +148,10 @@ bool DRC_TEST_PROVIDER_PHYSICAL_CLEARANCE::Run()
                 if( item->HasHole() )
                 {
                     if( layers.Contains( F_Cu ) )
-                        layers |= LSET::FrontBoardTechMask().set( F_CrtYd );
+                        layers |= LSET( LSET::FrontBoardTechMask() ).set( F_CrtYd );
 
                     if( layers.Contains( B_Cu ) )
-                        layers |= LSET::BackBoardTechMask().set( B_CrtYd );
+                        layers |= LSET( LSET::BackBoardTechMask() ).set( B_CrtYd );
 
                     if( layers.Contains( F_Cu ) && layers.Contains( B_Cu ) )
                         layers |= LSET::AllCuMask();
@@ -671,10 +671,10 @@ int DRC_TEST_PROVIDER_PHYSICAL_CLEARANCE::testItemAgainstItem( BOARD_ITEM* aItem
             LSET layers = aItem->GetLayerSet();
 
             if( layers.Contains( F_Cu ) )
-                layers |= LSET::FrontBoardTechMask().set( F_CrtYd );
+                layers |= LSET( LSET::FrontBoardTechMask() ).set( F_CrtYd );
 
             if( layers.Contains( B_Cu ) )
-                layers |= LSET::BackBoardTechMask().set( B_CrtYd );
+                layers |= LSET( LSET::BackBoardTechMask() ).set( B_CrtYd );
 
             if( layers.Contains( F_Cu ) && layers.Contains( B_Cu ) )
                 layers |= LSET::AllCuMask();
@@ -694,10 +694,10 @@ int DRC_TEST_PROVIDER_PHYSICAL_CLEARANCE::testItemAgainstItem( BOARD_ITEM* aItem
             LSET layers = aOther->GetLayerSet();
 
             if( layers.Contains( F_Cu ) )
-                layers |= LSET::FrontBoardTechMask().set( F_CrtYd );
+                layers |= LSET( LSET::FrontBoardTechMask() ).set( F_CrtYd );
 
             if( layers.Contains( B_Cu ) )
-                layers |= LSET::BackBoardTechMask().set( B_CrtYd );
+                layers |= LSET( LSET::BackBoardTechMask() ).set( B_CrtYd );
 
             if( layers.Contains( F_Cu ) && layers.Contains( B_Cu ) )
                 layers |= LSET::AllCuMask();
diff --git a/pcbnew/pad.cpp b/pcbnew/pad.cpp
index ae813fde26..de077b148b 100644
--- a/pcbnew/pad.cpp
+++ b/pcbnew/pad.cpp
@@ -342,7 +342,7 @@ PCB_LAYER_ID PAD::GetPrincipalLayer() const
 
 bool PAD::FlashLayer( LSET aLayers ) const
 {
-    for( PCB_LAYER_ID layer : aLayers.Seq() )
+    for( PCB_LAYER_ID layer : aLayers )
     {
         if( FlashLayer( layer ) )
             return true;
@@ -1760,7 +1760,7 @@ double PAD::ViewGetLOD( int aLayer, const KIGFX::VIEW* aView ) const
         return LOD_HIDE;
 
     // Handle Render tab switches
-    const PCB_LAYER_ID& pcbLayer = static_cast<PCB_LAYER_ID>( aLayer );
+    //const PCB_LAYER_ID& pcbLayer = static_cast<PCB_LAYER_ID>( aLayer );
 
     if( !IsFlipped() && !aView->IsLayerVisible( LAYER_FOOTPRINTS_FR ) )
         return LOD_HIDE;
@@ -1768,11 +1768,13 @@ double PAD::ViewGetLOD( int aLayer, const KIGFX::VIEW* aView ) const
     if( IsFlipped() && !aView->IsLayerVisible( LAYER_FOOTPRINTS_BK ) )
         return LOD_HIDE;
 
-    LSET visible = board->GetVisibleLayers() & board->GetEnabledLayers();
-
     if( IsHoleLayer( aLayer ) )
     {
-        if( !( visible & LSET::PhysicalLayersMask() ).any() )
+        LSET visiblePhysical = board->GetVisibleLayers();
+        visiblePhysical &= board->GetEnabledLayers();
+        visiblePhysical &= LSET::PhysicalLayersMask();
+
+        if( !visiblePhysical.any() )
             return LOD_HIDE;
     }
     else if( IsNetnameLayer( aLayer ) )
@@ -1785,6 +1787,9 @@ double PAD::ViewGetLOD( int aLayer, const KIGFX::VIEW* aView ) const
         }
         else
         {
+            LSET visible = board->GetVisibleLayers();
+            visible &= board->GetEnabledLayers();
+
             // Hide netnames unless pad is flashed to a visible layer
             if( !FlashLayer( visible ) )
                 return LOD_HIDE;
@@ -1807,8 +1812,10 @@ double PAD::ViewGetLOD( int aLayer, const KIGFX::VIEW* aView ) const
         }
     }
 
-    VECTOR2L padSize = GetShape( pcbLayer ) != PAD_SHAPE::CUSTOM
-                       ? VECTOR2L( GetSize( pcbLayer ) ) : GetBoundingBox().GetSize();
+    /*VECTOR2L padSize = GetShape( pcbLayer ) != PAD_SHAPE::CUSTOM
+                       ? VECTOR2L( GetSize( pcbLayer ) ) : GetBoundingBox().GetSize();*/
+
+    VECTOR2L padSize = GetBoundingBox().GetSize();
 
     int64_t minSide = std::min( padSize.x, padSize.y );
 
diff --git a/pcbnew/padstack.cpp b/pcbnew/padstack.cpp
index e66abdf4ea..0d2935e309 100644
--- a/pcbnew/padstack.cpp
+++ b/pcbnew/padstack.cpp
@@ -1036,11 +1036,13 @@ const PADSTACK::COPPER_LAYER_PROPS& PADSTACK::CopperLayer( PCB_LAYER_ID aLayer )
 {
     PCB_LAYER_ID layer = EffectiveLayerFor( aLayer );
 
-    wxCHECK_MSG( m_copperProps.contains( layer ), m_copperProps.at( ALL_LAYERS ),
+    auto it = m_copperProps.find( layer );
+
+    wxCHECK_MSG( it != m_copperProps.end(), m_copperProps.at( ALL_LAYERS ),
         "Attempt to retrieve layer " + std::string( magic_enum::enum_name( layer ) ) + " from a "
         "padstack that does not contain it" );
 
-    return m_copperProps.at( layer );
+    return it->second;
 }
 
 
diff --git a/pcbnew/pcb_io/eagle/pcb_io_eagle.cpp b/pcbnew/pcb_io/eagle/pcb_io_eagle.cpp
index b30843bbe1..74ba2faf7b 100644
--- a/pcbnew/pcb_io/eagle/pcb_io_eagle.cpp
+++ b/pcbnew/pcb_io/eagle/pcb_io_eagle.cpp
@@ -2495,7 +2495,7 @@ void PCB_IO_EAGLE::packageHole( FOOTPRINT* aFootprint, wxXmlNode* aTree, bool aC
     pad->SetDrillSize( sz );
     pad->SetSize( PADSTACK::ALL_LAYERS, sz );
 
-    pad->SetLayerSet( LSET::AllCuMask().set( B_Mask ).set( F_Mask ) );
+    pad->SetLayerSet( LSET( LSET::AllCuMask() ).set( B_Mask ).set( F_Mask ) );
 }
 
 
diff --git a/pcbnew/pcb_io/kicad_sexpr/pcb_io_kicad_sexpr_parser.cpp b/pcbnew/pcb_io/kicad_sexpr/pcb_io_kicad_sexpr_parser.cpp
index 0b7f0e2825..004e691b36 100644
--- a/pcbnew/pcb_io/kicad_sexpr/pcb_io_kicad_sexpr_parser.cpp
+++ b/pcbnew/pcb_io/kicad_sexpr/pcb_io_kicad_sexpr_parser.cpp
@@ -1159,7 +1159,7 @@ BOARD* PCB_IO_KICAD_SEXPR_PARSER::parseBOARD_unchecked()
             }
 
             // Make sure the destination layer is enabled, even if not in the file
-            m_board->SetEnabledLayers( m_board->GetEnabledLayers().set( destLayer ) );
+            m_board->SetEnabledLayers( LSET( m_board->GetEnabledLayers() ).set( destLayer ) );
 
             const auto visitItem = [&]( BOARD_ITEM& curr_item )
             {
diff --git a/pcbnew/pcb_track.cpp b/pcbnew/pcb_track.cpp
index 9db7b992bd..2e22166ba3 100644
--- a/pcbnew/pcb_track.cpp
+++ b/pcbnew/pcb_track.cpp
@@ -1228,15 +1228,10 @@ void PCB_VIA::SanitizeLayers()
 
 bool PCB_VIA::FlashLayer( LSET aLayers ) const
 {
-    for( size_t ii = 0; ii < aLayers.size(); ++ii )
+    for( PCB_LAYER_ID layer : aLayers )
     {
-        if( aLayers.test( ii ) )
-        {
-            PCB_LAYER_ID layer = PCB_LAYER_ID( ii );
-
-            if( FlashLayer( layer ) )
-                return true;
-        }
+        if( FlashLayer( layer ) )
+            return true;
     }
 
     return false;
diff --git a/pcbnew/widgets/appearance_controls.cpp b/pcbnew/widgets/appearance_controls.cpp
index f1e5491d5d..56eca47fa0 100644
--- a/pcbnew/widgets/appearance_controls.cpp
+++ b/pcbnew/widgets/appearance_controls.cpp
@@ -374,22 +374,22 @@ LAYER_PRESET APPEARANCE_CONTROLS::presetAllLayers( _HKI( "All Layers" ),
         LSET::AllLayersMask(), false );
 
 LAYER_PRESET APPEARANCE_CONTROLS::presetAllCopper( _HKI( "All Copper Layers" ),
-        LSET::AllCuMask().set( Edge_Cuts ), false );
+        LSET( LSET::AllCuMask() ).set( Edge_Cuts ), false );
 
 LAYER_PRESET APPEARANCE_CONTROLS::presetInnerCopper( _HKI( "Inner Copper Layers" ),
-        LSET::InternalCuMask().set( Edge_Cuts ), false );
+        LSET( LSET::InternalCuMask() ).set( Edge_Cuts ), false );
 
 LAYER_PRESET APPEARANCE_CONTROLS::presetFront( _HKI( "Front Layers" ),
-        LSET::FrontMask().set( Edge_Cuts ), false );
+        LSET( LSET::FrontMask() ).set( Edge_Cuts ), false );
 
 LAYER_PRESET APPEARANCE_CONTROLS::presetFrontAssembly( _HKI( "Front Assembly View" ),
-        LSET::FrontAssembly().set( Edge_Cuts ), GAL_SET::DefaultVisible(), F_SilkS, false );
+        LSET( LSET::FrontAssembly() ).set( Edge_Cuts ), GAL_SET::DefaultVisible(), F_SilkS, false );
 
 LAYER_PRESET APPEARANCE_CONTROLS::presetBack( _HKI( "Back Layers" ),
-        LSET::BackMask().set( Edge_Cuts ), true );
+        LSET( LSET::BackMask() ).set( Edge_Cuts ), true );
 
 LAYER_PRESET APPEARANCE_CONTROLS::presetBackAssembly( _HKI( "Back Assembly View" ),
-        LSET::BackAssembly().set( Edge_Cuts ), GAL_SET::DefaultVisible(), B_SilkS, true );
+        LSET( LSET::BackAssembly() ).set( Edge_Cuts ), GAL_SET::DefaultVisible(), B_SilkS, true );
 
 // this one is only used to store the object visibility settings  of the last used
 // built-in layer preset