diff --git a/src/app/commands/cmd_about.cpp b/src/app/commands/cmd_about.cpp
index c0f4a8a53..ba49c4775 100644
--- a/src/app/commands/cmd_about.cpp
+++ b/src/app/commands/cmd_about.cpp
@@ -32,7 +32,7 @@ using namespace ui;
 class AboutCommand : public Command {
 public:
   AboutCommand();
-  Command* clone() const { return new AboutCommand(*this); }
+  Command* clone() const OVERRIDE { return new AboutCommand(*this); }
 
 protected:
   void onExecute(Context* context);
diff --git a/src/app/commands/cmd_advanced_mode.cpp b/src/app/commands/cmd_advanced_mode.cpp
index d05639ad4..57a964727 100644
--- a/src/app/commands/cmd_advanced_mode.cpp
+++ b/src/app/commands/cmd_advanced_mode.cpp
@@ -38,7 +38,7 @@ using namespace ui;
 class AdvancedModeCommand : public Command {
 public:
   AdvancedModeCommand();
-  Command* clone() const { return new AdvancedModeCommand(*this); }
+  Command* clone() const OVERRIDE { return new AdvancedModeCommand(*this); }
 
 protected:
   void onExecute(Context* context);
diff --git a/src/app/commands/cmd_background_from_layer.cpp b/src/app/commands/cmd_background_from_layer.cpp
index a0a57385b..e304fbcb6 100644
--- a/src/app/commands/cmd_background_from_layer.cpp
+++ b/src/app/commands/cmd_background_from_layer.cpp
@@ -37,7 +37,7 @@ namespace app {
 class BackgroundFromLayerCommand : public Command {
 public:
   BackgroundFromLayerCommand();
-  Command* clone() const { return new BackgroundFromLayerCommand(*this); }
+  Command* clone() const OVERRIDE { return new BackgroundFromLayerCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_cancel.cpp b/src/app/commands/cmd_cancel.cpp
index 454a4a634..89f8ee70a 100644
--- a/src/app/commands/cmd_cancel.cpp
+++ b/src/app/commands/cmd_cancel.cpp
@@ -24,13 +24,14 @@
 
 #include "app/commands/commands.h"
 #include "app/context.h"
+#include "base/compiler_specific.h"
 
 namespace app {
 
 class CancelCommand : public Command {
 public:
   CancelCommand();
-  Command* clone() { return new CancelCommand(*this); }
+  Command* clone() const OVERRIDE { return new CancelCommand(*this); }
 
 protected:
   void onExecute(Context* context);
diff --git a/src/app/commands/cmd_canvas_size.cpp b/src/app/commands/cmd_canvas_size.cpp
index 84033bebf..c50fb87e0 100644
--- a/src/app/commands/cmd_canvas_size.cpp
+++ b/src/app/commands/cmd_canvas_size.cpp
@@ -149,7 +149,7 @@ class CanvasSizeCommand : public Command {
 
 public:
   CanvasSizeCommand();
-  Command* clone() const { return new CanvasSizeCommand(*this); }
+  Command* clone() const OVERRIDE { return new CanvasSizeCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_cel_properties.cpp b/src/app/commands/cmd_cel_properties.cpp
index a80a311cb..96f4ddf75 100644
--- a/src/app/commands/cmd_cel_properties.cpp
+++ b/src/app/commands/cmd_cel_properties.cpp
@@ -45,7 +45,7 @@ using namespace ui;
 class CelPropertiesCommand : public Command {
 public:
   CelPropertiesCommand();
-  Command* clone() const { return new CelPropertiesCommand(*this); }
+  Command* clone() const OVERRIDE { return new CelPropertiesCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_change_image_type.cpp b/src/app/commands/cmd_change_image_type.cpp
index e5dd00915..f8ac8ef9d 100644
--- a/src/app/commands/cmd_change_image_type.cpp
+++ b/src/app/commands/cmd_change_image_type.cpp
@@ -41,7 +41,7 @@ class ChangePixelFormatCommand : public Command {
   DitheringMethod m_dithering;
 public:
   ChangePixelFormatCommand();
-  Command* clone() const { return new ChangePixelFormatCommand(*this); }
+  Command* clone() const OVERRIDE { return new ChangePixelFormatCommand(*this); }
 
 protected:
   void onLoadParams(Params* params);
diff --git a/src/app/commands/cmd_clear.cpp b/src/app/commands/cmd_clear.cpp
index bec13ef1f..e4084dd3a 100644
--- a/src/app/commands/cmd_clear.cpp
+++ b/src/app/commands/cmd_clear.cpp
@@ -40,7 +40,7 @@ namespace app {
 class ClearCommand : public Command {
 public:
   ClearCommand();
-  Command* clone() const { return new ClearCommand(*this); }
+  Command* clone() const OVERRIDE { return new ClearCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_close_file.cpp b/src/app/commands/cmd_close_file.cpp
index b44a2d03b..994b9fa7b 100644
--- a/src/app/commands/cmd_close_file.cpp
+++ b/src/app/commands/cmd_close_file.cpp
@@ -52,7 +52,7 @@ public:
   {
   }
 
-  Command* clone() const { return new CloseFileCommand(*this); }
+  Command* clone() const OVERRIDE { return new CloseFileCommand(*this); }
 
 protected:
 
@@ -99,7 +99,7 @@ public:
   {
   }
 
-  Command* clone() const { return new CloseAllFilesCommand(*this); }
+  Command* clone() const OVERRIDE { return new CloseAllFilesCommand(*this); }
 
 protected:
 
diff --git a/src/app/commands/cmd_configure_tools.cpp b/src/app/commands/cmd_configure_tools.cpp
index 12ca05531..56cb50625 100644
--- a/src/app/commands/cmd_configure_tools.cpp
+++ b/src/app/commands/cmd_configure_tools.cpp
@@ -60,7 +60,7 @@ static void on_exit_delete_this_widget()
 class ConfigureTools : public Command {
 public:
   ConfigureTools();
-  Command* clone() const { return new ConfigureTools(*this); }
+  Command* clone() const OVERRIDE { return new ConfigureTools(*this); }
 
 protected:
   void onExecute(Context* context);
diff --git a/src/app/commands/cmd_copy.cpp b/src/app/commands/cmd_copy.cpp
index d53b8a1f0..a06066c23 100644
--- a/src/app/commands/cmd_copy.cpp
+++ b/src/app/commands/cmd_copy.cpp
@@ -34,7 +34,7 @@ namespace app {
 class CopyCommand : public Command {
 public:
   CopyCommand();
-  Command* clone() const { return new CopyCommand(*this); }
+  Command* clone() const OVERRIDE { return new CopyCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_copy_cel.cpp b/src/app/commands/cmd_copy_cel.cpp
index 4f5c59fd8..3d02ffb53 100644
--- a/src/app/commands/cmd_copy_cel.cpp
+++ b/src/app/commands/cmd_copy_cel.cpp
@@ -33,7 +33,7 @@ namespace app {
 class CopyCelCommand : public Command {
 public:
   CopyCelCommand();
-  Command* clone() const { return new CopyCelCommand(*this); }
+  Command* clone() const OVERRIDE { return new CopyCelCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_crop.cpp b/src/app/commands/cmd_crop.cpp
index 690012791..7df619076 100644
--- a/src/app/commands/cmd_crop.cpp
+++ b/src/app/commands/cmd_crop.cpp
@@ -40,7 +40,7 @@ namespace app {
 class CropSpriteCommand : public Command {
 public:
   CropSpriteCommand();
-  Command* clone() const { return new CropSpriteCommand(*this); }
+  Command* clone() const OVERRIDE { return new CropSpriteCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
@@ -81,7 +81,7 @@ void CropSpriteCommand::onExecute(Context* context)
 class AutocropSpriteCommand : public Command {
 public:
   AutocropSpriteCommand();
-  Command* clone() const { return new AutocropSpriteCommand(*this); }
+  Command* clone() const OVERRIDE { return new AutocropSpriteCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_cut.cpp b/src/app/commands/cmd_cut.cpp
index af481c92e..bdbc769e4 100644
--- a/src/app/commands/cmd_cut.cpp
+++ b/src/app/commands/cmd_cut.cpp
@@ -34,7 +34,7 @@ namespace app {
 class CutCommand : public Command {
 public:
   CutCommand();
-  Command* clone() const { return new CutCommand(*this); }
+  Command* clone() const OVERRIDE { return new CutCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_deselect_mask.cpp b/src/app/commands/cmd_deselect_mask.cpp
index 26ccf836c..a57d8e99f 100644
--- a/src/app/commands/cmd_deselect_mask.cpp
+++ b/src/app/commands/cmd_deselect_mask.cpp
@@ -33,7 +33,7 @@ namespace app {
 class DeselectMaskCommand : public Command {
 public:
   DeselectMaskCommand();
-  Command* clone() const { return new DeselectMaskCommand(*this); }
+  Command* clone() const OVERRIDE { return new DeselectMaskCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_duplicate_layer.cpp b/src/app/commands/cmd_duplicate_layer.cpp
index 762c28b9b..4faf22d56 100644
--- a/src/app/commands/cmd_duplicate_layer.cpp
+++ b/src/app/commands/cmd_duplicate_layer.cpp
@@ -41,7 +41,7 @@ namespace app {
 class DuplicateLayerCommand : public Command {
 public:
   DuplicateLayerCommand();
-  Command* clone() const { return new DuplicateLayerCommand(*this); }
+  Command* clone() const OVERRIDE { return new DuplicateLayerCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_duplicate_sprite.cpp b/src/app/commands/cmd_duplicate_sprite.cpp
index 701d9fec3..076371d6e 100644
--- a/src/app/commands/cmd_duplicate_sprite.cpp
+++ b/src/app/commands/cmd_duplicate_sprite.cpp
@@ -41,7 +41,7 @@ using namespace ui;
 class DuplicateSpriteCommand : public Command {
 public:
   DuplicateSpriteCommand();
-  Command* clone() { return new DuplicateSpriteCommand(*this); }
+  Command* clone() const OVERRIDE { return new DuplicateSpriteCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_exit.cpp b/src/app/commands/cmd_exit.cpp
index 86f8bd915..c92c491c7 100644
--- a/src/app/commands/cmd_exit.cpp
+++ b/src/app/commands/cmd_exit.cpp
@@ -32,7 +32,7 @@ namespace app {
 class ExitCommand : public Command {
 public:
   ExitCommand();
-  Command* clone() { return new ExitCommand(*this); }
+  Command* clone() const OVERRIDE { return new ExitCommand(*this); }
 
 protected:
   void onExecute(Context* context);
diff --git a/src/app/commands/cmd_eyedropper.cpp b/src/app/commands/cmd_eyedropper.cpp
index 01488b9a3..516cc7311 100644
--- a/src/app/commands/cmd_eyedropper.cpp
+++ b/src/app/commands/cmd_eyedropper.cpp
@@ -50,7 +50,7 @@ class EyedropperCommand : public Command {
 
 public:
   EyedropperCommand();
-  Command* clone() const { return new EyedropperCommand(*this); }
+  Command* clone() const OVERRIDE { return new EyedropperCommand(*this); }
 
 protected:
   void onLoadParams(Params* params);
diff --git a/src/app/commands/cmd_flatten_layers.cpp b/src/app/commands/cmd_flatten_layers.cpp
index 8998bfbf5..bac1d163b 100644
--- a/src/app/commands/cmd_flatten_layers.cpp
+++ b/src/app/commands/cmd_flatten_layers.cpp
@@ -35,7 +35,7 @@ namespace app {
 class FlattenLayersCommand : public Command {
 public:
   FlattenLayersCommand();
-  Command* clone() { return new FlattenLayersCommand(*this); }
+  Command* clone() const OVERRIDE { return new FlattenLayersCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_flip.h b/src/app/commands/cmd_flip.h
index 64172783d..d15bde8d2 100644
--- a/src/app/commands/cmd_flip.h
+++ b/src/app/commands/cmd_flip.h
@@ -20,6 +20,7 @@
 #define APP_COMMANDS_CMD_FLIP_H_INCLUDED
 
 #include "app/commands/command.h"
+#include "base/compiler_specific.h"
 #include "raster/algorithm/flip_type.h"
 
 namespace app {
@@ -27,7 +28,7 @@ namespace app {
   class FlipCommand : public Command {
   public:
     FlipCommand();
-    Command* clone() const { return new FlipCommand(*this); }
+    Command* clone() const OVERRIDE { return new FlipCommand(*this); }
 
     raster::algorithm::FlipType getFlipType() const { return m_flipType; }
 
diff --git a/src/app/commands/cmd_frame_properties.cpp b/src/app/commands/cmd_frame_properties.cpp
index 33559a4ec..0481bed93 100644
--- a/src/app/commands/cmd_frame_properties.cpp
+++ b/src/app/commands/cmd_frame_properties.cpp
@@ -41,7 +41,7 @@ using namespace ui;
 class FramePropertiesCommand : public Command {
 public:
   FramePropertiesCommand();
-  Command* clone() { return new FramePropertiesCommand(*this); }
+  Command* clone() const OVERRIDE { return new FramePropertiesCommand(*this); }
 
 protected:
   void onLoadParams(Params* params);
diff --git a/src/app/commands/cmd_goto_frame.cpp b/src/app/commands/cmd_goto_frame.cpp
index 4a7edb6f0..e3f12eb76 100644
--- a/src/app/commands/cmd_goto_frame.cpp
+++ b/src/app/commands/cmd_goto_frame.cpp
@@ -62,7 +62,7 @@ public:
   GotoFirstFrameCommand()
     : GotoCommand("GotoFirstFrame",
                   "Goto First Frame") { }
-  Command* clone() { return new GotoFirstFrameCommand(*this); }
+  Command* clone() const OVERRIDE { return new GotoFirstFrameCommand(*this); }
 
 protected:
   FrameNumber onGetFrame(Editor* editor) OVERRIDE {
@@ -79,7 +79,7 @@ public:
   GotoPreviousFrameCommand()
     : GotoCommand("GotoPreviousFrame",
                   "Goto Previous Frame") { }
-  Command* clone() { return new GotoPreviousFrameCommand(*this); }
+  Command* clone() const OVERRIDE { return new GotoPreviousFrameCommand(*this); }
 
 protected:
   FrameNumber onGetFrame(Editor* editor) OVERRIDE {
@@ -100,7 +100,7 @@ class GotoNextFrameCommand : public GotoCommand
 public:
   GotoNextFrameCommand() : GotoCommand("GotoNextFrame",
                                        "Goto Next Frame") { }
-  Command* clone() { return new GotoNextFrameCommand(*this); }
+  Command* clone() const OVERRIDE { return new GotoNextFrameCommand(*this); }
 
 protected:
   FrameNumber onGetFrame(Editor* editor) OVERRIDE {
@@ -119,7 +119,7 @@ class GotoLastFrameCommand : public GotoCommand
 public:
   GotoLastFrameCommand() : GotoCommand("GotoLastFrame",
                                        "Goto Last Frame") { }
-  Command* clone() { return new GotoLastFrameCommand(*this); }
+  Command* clone() const OVERRIDE { return new GotoLastFrameCommand(*this); }
 
 protected:
   FrameNumber onGetFrame(Editor* editor) OVERRIDE {
@@ -136,7 +136,7 @@ public:
   GotoFrameCommand() : GotoCommand("GotoFrame",
                                    "Goto Frame")
                      , m_frame(0) { }
-  Command* clone() { return new GotoFrameCommand(*this); }
+  Command* clone() const OVERRIDE { return new GotoFrameCommand(*this); }
 
 protected:
   void onLoadParams(Params* params) OVERRIDE
diff --git a/src/app/commands/cmd_goto_layer.cpp b/src/app/commands/cmd_goto_layer.cpp
index b5af2b4c1..e0c0836dd 100644
--- a/src/app/commands/cmd_goto_layer.cpp
+++ b/src/app/commands/cmd_goto_layer.cpp
@@ -50,7 +50,7 @@ protected:
 class GotoPreviousLayerCommand : public GotoCommand {
 public:
   GotoPreviousLayerCommand();
-  Command* clone() { return new GotoPreviousLayerCommand(*this); }
+  Command* clone() const OVERRIDE { return new GotoPreviousLayerCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
@@ -92,7 +92,7 @@ void GotoPreviousLayerCommand::onExecute(Context* context)
 class GotoNextLayerCommand : public GotoCommand {
 public:
   GotoNextLayerCommand();
-  Command* clone() { return new GotoNextLayerCommand(*this); }
+  Command* clone() const OVERRIDE { return new GotoNextLayerCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_goto_tab.cpp b/src/app/commands/cmd_goto_tab.cpp
index 29d2aaabe..1482f0769 100644
--- a/src/app/commands/cmd_goto_tab.cpp
+++ b/src/app/commands/cmd_goto_tab.cpp
@@ -31,7 +31,7 @@ namespace app {
 class GotoNextTabCommand : public Command {
 public:
   GotoNextTabCommand();
-  Command* clone() { return new GotoNextTabCommand(*this); }
+  Command* clone() const OVERRIDE { return new GotoNextTabCommand(*this); }
 
 protected:
   void onExecute(Context* context);
@@ -52,7 +52,7 @@ void GotoNextTabCommand::onExecute(Context* context)
 class GotoPreviousTabCommand : public Command {
 public:
   GotoPreviousTabCommand();
-  Command* clone() { return new GotoPreviousTabCommand(*this); }
+  Command* clone() const OVERRIDE { return new GotoPreviousTabCommand(*this); }
 
 protected:
   void onExecute(Context* context);
diff --git a/src/app/commands/cmd_grid.cpp b/src/app/commands/cmd_grid.cpp
index 15c5877b1..104628261 100644
--- a/src/app/commands/cmd_grid.cpp
+++ b/src/app/commands/cmd_grid.cpp
@@ -48,7 +48,7 @@ public:
   {
   }
 
-  Command* clone() const { return new ShowGridCommand(*this); }
+  Command* clone() const OVERRIDE { return new ShowGridCommand(*this); }
 
 protected:
   bool onChecked(Context* context)
@@ -75,7 +75,7 @@ public:
   {
   }
 
-  Command* clone() const { return new SnapToGridCommand(*this); }
+  Command* clone() const OVERRIDE { return new SnapToGridCommand(*this); }
 
 protected:
   bool onChecked(Context* context)
@@ -102,7 +102,7 @@ protected:
 class GridSettingsCommand : public Command {
 public:
   GridSettingsCommand();
-  Command* clone() const { return new GridSettingsCommand(*this); }
+  Command* clone() const OVERRIDE { return new GridSettingsCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_import_sprite_sheet.cpp b/src/app/commands/cmd_import_sprite_sheet.cpp
index a4cbc9e21..981021cb2 100644
--- a/src/app/commands/cmd_import_sprite_sheet.cpp
+++ b/src/app/commands/cmd_import_sprite_sheet.cpp
@@ -348,7 +348,7 @@ private:
 class ImportSpriteSheetCommand : public Command {
 public:
   ImportSpriteSheetCommand();
-  Command* clone() { return new ImportSpriteSheetCommand(*this); }
+  Command* clone() const OVERRIDE { return new ImportSpriteSheetCommand(*this); }
 
 protected:
   virtual void onExecute(Context* context) OVERRIDE;
diff --git a/src/app/commands/cmd_invert_mask.cpp b/src/app/commands/cmd_invert_mask.cpp
index bbad613f6..d95fe7906 100644
--- a/src/app/commands/cmd_invert_mask.cpp
+++ b/src/app/commands/cmd_invert_mask.cpp
@@ -37,7 +37,7 @@ namespace app {
 class InvertMaskCommand : public Command {
 public:
   InvertMaskCommand();
-  Command* clone() { return new InvertMaskCommand(*this); }
+  Command* clone() const OVERRIDE { return new InvertMaskCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_launch.cpp b/src/app/commands/cmd_launch.cpp
index 2832f6fb6..c6241a198 100644
--- a/src/app/commands/cmd_launch.cpp
+++ b/src/app/commands/cmd_launch.cpp
@@ -32,7 +32,7 @@ namespace app {
 class LaunchCommand : public Command {
 public:
   LaunchCommand();
-  Command* clone() const { return new LaunchCommand(*this); }
+  Command* clone() const OVERRIDE { return new LaunchCommand(*this); }
 
 protected:
   void onLoadParams(Params* params) OVERRIDE;
diff --git a/src/app/commands/cmd_layer_from_background.cpp b/src/app/commands/cmd_layer_from_background.cpp
index ffa89699e..f9df78306 100644
--- a/src/app/commands/cmd_layer_from_background.cpp
+++ b/src/app/commands/cmd_layer_from_background.cpp
@@ -34,7 +34,7 @@ namespace app {
 class LayerFromBackgroundCommand : public Command {
 public:
   LayerFromBackgroundCommand();
-  Command* clone() { return new LayerFromBackgroundCommand(*this); }
+  Command* clone() const OVERRIDE { return new LayerFromBackgroundCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_layer_properties.cpp b/src/app/commands/cmd_layer_properties.cpp
index e24679f39..3a969b0ba 100644
--- a/src/app/commands/cmd_layer_properties.cpp
+++ b/src/app/commands/cmd_layer_properties.cpp
@@ -37,7 +37,7 @@ using namespace ui;
 class LayerPropertiesCommand : public Command {
 public:
   LayerPropertiesCommand();
-  Command* clone() { return new LayerPropertiesCommand(*this); }
+  Command* clone() const OVERRIDE { return new LayerPropertiesCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_load_mask.cpp b/src/app/commands/cmd_load_mask.cpp
index 3a4b00b29..266582633 100644
--- a/src/app/commands/cmd_load_mask.cpp
+++ b/src/app/commands/cmd_load_mask.cpp
@@ -39,7 +39,7 @@ class LoadMaskCommand : public Command {
 
 public:
   LoadMaskCommand();
-  Command* clone() const { return new LoadMaskCommand(*this); }
+  Command* clone() const OVERRIDE { return new LoadMaskCommand(*this); }
 
 protected:
   void onLoadParams(Params* params);
diff --git a/src/app/commands/cmd_load_palette.cpp b/src/app/commands/cmd_load_palette.cpp
index b574af385..f2d790e3f 100644
--- a/src/app/commands/cmd_load_palette.cpp
+++ b/src/app/commands/cmd_load_palette.cpp
@@ -40,7 +40,7 @@ using namespace ui;
 class LoadPaletteCommand : public Command {
 public:
   LoadPaletteCommand();
-  Command* clone() { return new LoadPaletteCommand(*this); }
+  Command* clone() const OVERRIDE { return new LoadPaletteCommand(*this); }
 
 protected:
   void onExecute(Context* context) OVERRIDE;
diff --git a/src/app/commands/cmd_mask_all.cpp b/src/app/commands/cmd_mask_all.cpp
index 7b26ad5f9..6b8f6b8e0 100644
--- a/src/app/commands/cmd_mask_all.cpp
+++ b/src/app/commands/cmd_mask_all.cpp
@@ -33,7 +33,7 @@ namespace app {
 class MaskAllCommand : public Command {
 public:
   MaskAllCommand();
-  Command* clone() { return new MaskAllCommand(*this); }
+  Command* clone() const OVERRIDE { return new MaskAllCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_mask_by_color.cpp b/src/app/commands/cmd_mask_by_color.cpp
index 6006a23ff..f6d9df86c 100644
--- a/src/app/commands/cmd_mask_by_color.cpp
+++ b/src/app/commands/cmd_mask_by_color.cpp
@@ -54,7 +54,7 @@ using namespace ui;
 class MaskByColorCommand : public Command {
 public:
   MaskByColorCommand();
-  Command* clone() { return new MaskByColorCommand(*this); }
+  Command* clone() const OVERRIDE { return new MaskByColorCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_merge_down_layer.cpp b/src/app/commands/cmd_merge_down_layer.cpp
index c22b8b392..1b3472b21 100644
--- a/src/app/commands/cmd_merge_down_layer.cpp
+++ b/src/app/commands/cmd_merge_down_layer.cpp
@@ -46,7 +46,7 @@ namespace app {
 class MergeDownLayerCommand : public Command {
 public:
   MergeDownLayerCommand();
-  Command* clone() { return new MergeDownLayerCommand(*this); }
+  Command* clone() const OVERRIDE { return new MergeDownLayerCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_move_cel.cpp b/src/app/commands/cmd_move_cel.cpp
index 0778b5b13..d5eaa0590 100644
--- a/src/app/commands/cmd_move_cel.cpp
+++ b/src/app/commands/cmd_move_cel.cpp
@@ -33,7 +33,7 @@ namespace app {
 class MoveCelCommand : public Command {
 public:
   MoveCelCommand();
-  Command* clone() const { return new MoveCelCommand(*this); }
+  Command* clone() const OVERRIDE { return new MoveCelCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_new_file.cpp b/src/app/commands/cmd_new_file.cpp
index 860c2378a..42bb87367 100644
--- a/src/app/commands/cmd_new_file.cpp
+++ b/src/app/commands/cmd_new_file.cpp
@@ -55,7 +55,7 @@ namespace app {
 class NewFileCommand : public Command {
 public:
   NewFileCommand();
-  Command* clone() { return new NewFileCommand(*this); }
+  Command* clone() const OVERRIDE { return new NewFileCommand(*this); }
 
 protected:
   void onExecute(Context* context);
diff --git a/src/app/commands/cmd_new_frame.cpp b/src/app/commands/cmd_new_frame.cpp
index 86687908f..01d27c941 100644
--- a/src/app/commands/cmd_new_frame.cpp
+++ b/src/app/commands/cmd_new_frame.cpp
@@ -43,7 +43,7 @@ namespace app {
 class NewFrameCommand : public Command {
 public:
   NewFrameCommand();
-  Command* clone() { return new NewFrameCommand(*this); }
+  Command* clone() const OVERRIDE { return new NewFrameCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_new_layer.cpp b/src/app/commands/cmd_new_layer.cpp
index c9949918c..a6ccf9e5c 100644
--- a/src/app/commands/cmd_new_layer.cpp
+++ b/src/app/commands/cmd_new_layer.cpp
@@ -44,7 +44,7 @@ using namespace ui;
 class NewLayerCommand : public Command {
 public:
   NewLayerCommand();
-  Command* clone() { return new NewLayerCommand(*this); }
+  Command* clone() const OVERRIDE { return new NewLayerCommand(*this); }
 
 protected:
   void onLoadParams(Params* params);
diff --git a/src/app/commands/cmd_new_layer_set.cpp b/src/app/commands/cmd_new_layer_set.cpp
index df91659cf..e0e3c41e2 100644
--- a/src/app/commands/cmd_new_layer_set.cpp
+++ b/src/app/commands/cmd_new_layer_set.cpp
@@ -41,7 +41,7 @@ using namespace ui;
 class NewLayerSetCommand : public Command {
 public:
   NewLayerSetCommand();
-  Command* clone() { return new NewLayerSetCommand(*this); }
+  Command* clone() const OVERRIDE { return new NewLayerSetCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_open_file.cpp b/src/app/commands/cmd_open_file.cpp
index 64948d9b8..4ac03c43d 100644
--- a/src/app/commands/cmd_open_file.cpp
+++ b/src/app/commands/cmd_open_file.cpp
@@ -48,7 +48,7 @@ namespace app {
 class OpenFileCommand : public Command {
 public:
   OpenFileCommand();
-  Command* clone() { return new OpenFileCommand(*this); }
+  Command* clone() const OVERRIDE { return new OpenFileCommand(*this); }
 
 protected:
   void onLoadParams(Params* params);
diff --git a/src/app/commands/cmd_open_in_folder.cpp b/src/app/commands/cmd_open_in_folder.cpp
index 06632f4e3..b3ca71163 100644
--- a/src/app/commands/cmd_open_in_folder.cpp
+++ b/src/app/commands/cmd_open_in_folder.cpp
@@ -32,7 +32,7 @@ namespace app {
 class OpenInFolderCommand : public Command {
 public:
   OpenInFolderCommand();
-  Command* clone() { return new OpenInFolderCommand(*this); }
+  Command* clone() const OVERRIDE { return new OpenInFolderCommand(*this); }
 
 protected:
   bool onEnabled(Context* context) OVERRIDE;
diff --git a/src/app/commands/cmd_open_with_app.cpp b/src/app/commands/cmd_open_with_app.cpp
index 935103c19..69c4ec5c4 100644
--- a/src/app/commands/cmd_open_with_app.cpp
+++ b/src/app/commands/cmd_open_with_app.cpp
@@ -32,7 +32,7 @@ namespace app {
 class OpenWithAppCommand : public Command {
 public:
   OpenWithAppCommand();
-  Command* clone() { return new OpenWithAppCommand(*this); }
+  Command* clone() const OVERRIDE { return new OpenWithAppCommand(*this); }
 
 protected:
   bool onEnabled(Context* context) OVERRIDE;
diff --git a/src/app/commands/cmd_options.cpp b/src/app/commands/cmd_options.cpp
index c44328b12..dc15a5c19 100644
--- a/src/app/commands/cmd_options.cpp
+++ b/src/app/commands/cmd_options.cpp
@@ -44,7 +44,7 @@ using namespace ui;
 class OptionsCommand : public Command {
 public:
   OptionsCommand();
-  Command* clone() { return new OptionsCommand(*this); }
+  Command* clone() const OVERRIDE { return new OptionsCommand(*this); }
 
 protected:
   void onExecute(Context* context);
diff --git a/src/app/commands/cmd_palette_editor.cpp b/src/app/commands/cmd_palette_editor.cpp
index 8ac35acc6..7e973264e 100644
--- a/src/app/commands/cmd_palette_editor.cpp
+++ b/src/app/commands/cmd_palette_editor.cpp
@@ -146,7 +146,7 @@ static PaletteEntryEditor* g_window = NULL;
 class PaletteEditorCommand : public Command {
 public:
   PaletteEditorCommand();
-  Command* clone() { return new PaletteEditorCommand(*this); }
+  Command* clone() const OVERRIDE { return new PaletteEditorCommand(*this); }
 
 protected:
   void onLoadParams(Params* params) OVERRIDE;
diff --git a/src/app/commands/cmd_paste.cpp b/src/app/commands/cmd_paste.cpp
index f6ac83044..b959da3f6 100644
--- a/src/app/commands/cmd_paste.cpp
+++ b/src/app/commands/cmd_paste.cpp
@@ -23,6 +23,7 @@
 #include "app/commands/command.h"
 #include "app/context.h"
 #include "app/util/clipboard.h"
+#include "base/compiler_specific.h"
 #include "raster/layer.h"
 #include "raster/sprite.h"
 
@@ -31,7 +32,7 @@ namespace app {
 class PasteCommand : public Command {
 public:
   PasteCommand();
-  Command* clone() { return new PasteCommand(*this); }
+  Command* clone() const OVERRIDE { return new PasteCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_play_animation.cpp b/src/app/commands/cmd_play_animation.cpp
index 5c13ff14e..7092d64c7 100644
--- a/src/app/commands/cmd_play_animation.cpp
+++ b/src/app/commands/cmd_play_animation.cpp
@@ -43,7 +43,7 @@ namespace app {
 class PlayAnimationCommand : public Command {
 public:
   PlayAnimationCommand();
-  Command* clone() { return new PlayAnimationCommand(*this); }
+  Command* clone() const OVERRIDE { return new PlayAnimationCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_preview.cpp b/src/app/commands/cmd_preview.cpp
index 22379a32a..91c30411f 100644
--- a/src/app/commands/cmd_preview.cpp
+++ b/src/app/commands/cmd_preview.cpp
@@ -55,7 +55,7 @@ using namespace filters;
 class PreviewCommand : public Command {
 public:
   PreviewCommand();
-  Command* clone() { return new PreviewCommand(*this); }
+  Command* clone() const OVERRIDE { return new PreviewCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_refresh.cpp b/src/app/commands/cmd_refresh.cpp
index 6c363ca67..0bcb8420f 100644
--- a/src/app/commands/cmd_refresh.cpp
+++ b/src/app/commands/cmd_refresh.cpp
@@ -40,7 +40,7 @@ namespace app {
 class RefreshCommand : public Command {
 public:
   RefreshCommand();
-  Command* clone() { return new RefreshCommand(*this); }
+  Command* clone() const OVERRIDE { return new RefreshCommand(*this); }
 
 protected:
   void onExecute(Context* context);
diff --git a/src/app/commands/cmd_remove_cel.cpp b/src/app/commands/cmd_remove_cel.cpp
index c53119d72..9a2edd464 100644
--- a/src/app/commands/cmd_remove_cel.cpp
+++ b/src/app/commands/cmd_remove_cel.cpp
@@ -37,7 +37,7 @@ namespace app {
 class RemoveCelCommand : public Command {
 public:
   RemoveCelCommand();
-  Command* clone() { return new RemoveCelCommand(*this); }
+  Command* clone() const OVERRIDE { return new RemoveCelCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_remove_frame.cpp b/src/app/commands/cmd_remove_frame.cpp
index eb77a8118..9e499833f 100644
--- a/src/app/commands/cmd_remove_frame.cpp
+++ b/src/app/commands/cmd_remove_frame.cpp
@@ -36,7 +36,7 @@ namespace app {
 class RemoveFrameCommand : public Command {
 public:
   RemoveFrameCommand();
-  Command* clone() { return new RemoveFrameCommand(*this); }
+  Command* clone() const OVERRIDE { return new RemoveFrameCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_remove_layer.cpp b/src/app/commands/cmd_remove_layer.cpp
index 3566262ce..80482c2ea 100644
--- a/src/app/commands/cmd_remove_layer.cpp
+++ b/src/app/commands/cmd_remove_layer.cpp
@@ -38,7 +38,7 @@ namespace app {
 class RemoveLayerCommand : public Command {
 public:
   RemoveLayerCommand();
-  Command* clone() { return new RemoveLayerCommand(*this); }
+  Command* clone() const OVERRIDE { return new RemoveLayerCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_repeat_last_export.cpp b/src/app/commands/cmd_repeat_last_export.cpp
index e65f7d65e..d2d27fd07 100644
--- a/src/app/commands/cmd_repeat_last_export.cpp
+++ b/src/app/commands/cmd_repeat_last_export.cpp
@@ -33,7 +33,7 @@ namespace app {
 class RepeatLastExportCommand : public Command {
 public:
   RepeatLastExportCommand();
-  Command* clone() { return new RepeatLastExportCommand(*this); }
+  Command* clone() const OVERRIDE { return new RepeatLastExportCommand(*this); }
 
 protected:
   virtual bool onEnabled(Context* context) OVERRIDE;
diff --git a/src/app/commands/cmd_reselect_mask.cpp b/src/app/commands/cmd_reselect_mask.cpp
index e588b6d25..b8f9f1a48 100644
--- a/src/app/commands/cmd_reselect_mask.cpp
+++ b/src/app/commands/cmd_reselect_mask.cpp
@@ -33,7 +33,7 @@ namespace app {
 class ReselectMaskCommand : public Command {
 public:
   ReselectMaskCommand();
-  Command* clone() { return new ReselectMaskCommand(*this); }
+  Command* clone() const OVERRIDE { return new ReselectMaskCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_rotate_canvas.cpp b/src/app/commands/cmd_rotate_canvas.cpp
index 87148db7f..5d53aab26 100644
--- a/src/app/commands/cmd_rotate_canvas.cpp
+++ b/src/app/commands/cmd_rotate_canvas.cpp
@@ -45,7 +45,7 @@ class RotateCanvasCommand : public Command {
 
 public:
   RotateCanvasCommand();
-  Command* clone() { return new RotateCanvasCommand(*this); }
+  Command* clone() const OVERRIDE { return new RotateCanvasCommand(*this); }
 
 protected:
   void onLoadParams(Params* params);
diff --git a/src/app/commands/cmd_save_file.cpp b/src/app/commands/cmd_save_file.cpp
index e51f87035..96fc154c8 100644
--- a/src/app/commands/cmd_save_file.cpp
+++ b/src/app/commands/cmd_save_file.cpp
@@ -207,7 +207,7 @@ protected:
 class SaveFileCommand : public SaveFileBaseCommand {
 public:
   SaveFileCommand();
-  Command* clone() { return new SaveFileCommand(*this); }
+  Command* clone() const OVERRIDE { return new SaveFileCommand(*this); }
 
 protected:
   void onExecute(Context* context);
@@ -248,7 +248,7 @@ void SaveFileCommand::onExecute(Context* context)
 class SaveFileAsCommand : public SaveFileBaseCommand {
 public:
   SaveFileAsCommand();
-  Command* clone() { return new SaveFileAsCommand(*this); }
+  Command* clone() const OVERRIDE { return new SaveFileAsCommand(*this); }
 
 protected:
   void onExecute(Context* context);
@@ -268,7 +268,7 @@ void SaveFileAsCommand::onExecute(Context* context)
 class SaveFileCopyAsCommand : public SaveFileBaseCommand {
 public:
   SaveFileCopyAsCommand();
-  Command* clone() { return new SaveFileCopyAsCommand(*this); }
+  Command* clone() const OVERRIDE { return new SaveFileCopyAsCommand(*this); }
 
 protected:
   void onExecute(Context* context);
diff --git a/src/app/commands/cmd_save_mask.cpp b/src/app/commands/cmd_save_mask.cpp
index 2f0160a8a..e7aab43e5 100644
--- a/src/app/commands/cmd_save_mask.cpp
+++ b/src/app/commands/cmd_save_mask.cpp
@@ -35,7 +35,7 @@ namespace app {
 class SaveMaskCommand : public Command {
 public:
   SaveMaskCommand();
-  Command* clone() { return new SaveMaskCommand(*this); }
+  Command* clone() const OVERRIDE { return new SaveMaskCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_save_palette.cpp b/src/app/commands/cmd_save_palette.cpp
index 85f051f98..b374bb1a2 100644
--- a/src/app/commands/cmd_save_palette.cpp
+++ b/src/app/commands/cmd_save_palette.cpp
@@ -36,7 +36,7 @@ using namespace ui;
 class SavePaletteCommand : public Command {
 public:
   SavePaletteCommand();
-  Command* clone() { return new SavePaletteCommand(*this); }
+  Command* clone() const OVERRIDE { return new SavePaletteCommand(*this); }
 
 protected:
   void onExecute(Context* context) OVERRIDE;
diff --git a/src/app/commands/cmd_scroll.cpp b/src/app/commands/cmd_scroll.cpp
index 263917b20..b49f5491b 100644
--- a/src/app/commands/cmd_scroll.cpp
+++ b/src/app/commands/cmd_scroll.cpp
@@ -46,7 +46,7 @@ public:
   };
 
   ScrollCommand();
-  Command* clone() { return new ScrollCommand(*this); }
+  Command* clone() const OVERRIDE { return new ScrollCommand(*this); }
 
 protected:
   void onLoadParams(Params* params);
diff --git a/src/app/commands/cmd_sprite_editor.cpp b/src/app/commands/cmd_sprite_editor.cpp
index d11a8bf7c..3f714d697 100644
--- a/src/app/commands/cmd_sprite_editor.cpp
+++ b/src/app/commands/cmd_sprite_editor.cpp
@@ -31,7 +31,7 @@ namespace app {
 class MakeUniqueEditorCommand : public Command {
 public:
   MakeUniqueEditorCommand();
-  Command* clone() { return new MakeUniqueEditorCommand(*this); }
+  Command* clone() const OVERRIDE { return new MakeUniqueEditorCommand(*this); }
 
 protected:
   void onExecute(Context* context);
@@ -54,7 +54,7 @@ void MakeUniqueEditorCommand::onExecute(Context* context)
 class SplitEditorHorizontallyCommand : public Command {
 public:
   SplitEditorHorizontallyCommand();
-  Command* clone() { return new SplitEditorHorizontallyCommand(*this); }
+  Command* clone() const OVERRIDE { return new SplitEditorHorizontallyCommand(*this); }
 
 protected:
   void onExecute(Context* context);
@@ -77,7 +77,7 @@ void SplitEditorHorizontallyCommand::onExecute(Context* context)
 class SplitEditorVerticallyCommand : public Command {
 public:
   SplitEditorVerticallyCommand();
-  Command* clone() { return new SplitEditorVerticallyCommand(*this); }
+  Command* clone() const OVERRIDE { return new SplitEditorVerticallyCommand(*this); }
 
 protected:
   void onExecute(Context* context);
diff --git a/src/app/commands/cmd_sprite_properties.cpp b/src/app/commands/cmd_sprite_properties.cpp
index 33d60118c..6f6500b99 100644
--- a/src/app/commands/cmd_sprite_properties.cpp
+++ b/src/app/commands/cmd_sprite_properties.cpp
@@ -44,7 +44,7 @@ using namespace ui;
 class SpritePropertiesCommand : public Command {
 public:
   SpritePropertiesCommand();
-  Command* clone() { return new SpritePropertiesCommand(*this); }
+  Command* clone() const OVERRIDE { return new SpritePropertiesCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_sprite_size.cpp b/src/app/commands/cmd_sprite_size.cpp
index 0f2ec10bf..694f941eb 100644
--- a/src/app/commands/cmd_sprite_size.cpp
+++ b/src/app/commands/cmd_sprite_size.cpp
@@ -162,7 +162,7 @@ protected:
 class SpriteSizeCommand : public Command {
 public:
   SpriteSizeCommand();
-  Command* clone() { return new SpriteSizeCommand(*this); }
+  Command* clone() const OVERRIDE { return new SpriteSizeCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/cmd_timeline.cpp b/src/app/commands/cmd_timeline.cpp
index a90cecc52..d4e504855 100644
--- a/src/app/commands/cmd_timeline.cpp
+++ b/src/app/commands/cmd_timeline.cpp
@@ -34,7 +34,7 @@ namespace app {
 class TimelineCommand : public Command {
 public:
   TimelineCommand();
-  Command* clone() { return new TimelineCommand(*this); }
+  Command* clone() const OVERRIDE { return new TimelineCommand(*this); }
 
 protected:
   void onLoadParams(Params* params) OVERRIDE;
diff --git a/src/app/commands/cmd_undo.cpp b/src/app/commands/cmd_undo.cpp
index e55e71037..687223b86 100644
--- a/src/app/commands/cmd_undo.cpp
+++ b/src/app/commands/cmd_undo.cpp
@@ -40,7 +40,7 @@ public:
   enum Type { Undo, Redo };
 
   UndoCommand(Type type);
-  Command* clone() { return new UndoCommand(*this); }
+  Command* clone() const OVERRIDE { return new UndoCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/filters/cmd_color_curve.cpp b/src/app/commands/filters/cmd_color_curve.cpp
index 91c21d384..bae19130e 100644
--- a/src/app/commands/filters/cmd_color_curve.cpp
+++ b/src/app/commands/filters/cmd_color_curve.cpp
@@ -89,7 +89,7 @@ private:
 class ColorCurveCommand : public Command {
 public:
   ColorCurveCommand();
-  Command* clone() const { return new ColorCurveCommand(*this); }
+  Command* clone() const OVERRIDE { return new ColorCurveCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/filters/cmd_convolution_matrix.cpp b/src/app/commands/filters/cmd_convolution_matrix.cpp
index 3d7169387..338c4332b 100644
--- a/src/app/commands/filters/cmd_convolution_matrix.cpp
+++ b/src/app/commands/filters/cmd_convolution_matrix.cpp
@@ -156,7 +156,7 @@ private:
 class ConvolutionMatrixCommand : public Command {
 public:
   ConvolutionMatrixCommand();
-  Command* clone() const { return new ConvolutionMatrixCommand(*this); }
+  Command* clone() const OVERRIDE { return new ConvolutionMatrixCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/filters/cmd_despeckle.cpp b/src/app/commands/filters/cmd_despeckle.cpp
index ae9a1f7c1..05abedb9b 100644
--- a/src/app/commands/filters/cmd_despeckle.cpp
+++ b/src/app/commands/filters/cmd_despeckle.cpp
@@ -94,7 +94,7 @@ class DespeckleCommand : public Command
 {
 public:
   DespeckleCommand();
-  Command* clone() const { return new DespeckleCommand(*this); }
+  Command* clone() const OVERRIDE { return new DespeckleCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/filters/cmd_invert_color.cpp b/src/app/commands/filters/cmd_invert_color.cpp
index a5dac6db8..87bff6dde 100644
--- a/src/app/commands/filters/cmd_invert_color.cpp
+++ b/src/app/commands/filters/cmd_invert_color.cpp
@@ -60,7 +60,7 @@ private:
 class InvertColorCommand : public Command {
 public:
   InvertColorCommand();
-  Command* clone() const { return new InvertColorCommand(*this); }
+  Command* clone() const OVERRIDE { return new InvertColorCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);
diff --git a/src/app/commands/filters/cmd_replace_color.cpp b/src/app/commands/filters/cmd_replace_color.cpp
index aab47bb70..fb4d6e9dc 100644
--- a/src/app/commands/filters/cmd_replace_color.cpp
+++ b/src/app/commands/filters/cmd_replace_color.cpp
@@ -121,7 +121,7 @@ private:
 class ReplaceColorCommand : public Command {
 public:
   ReplaceColorCommand();
-  Command* clone() const { return new ReplaceColorCommand(*this); }
+  Command* clone() const OVERRIDE { return new ReplaceColorCommand(*this); }
 
 protected:
   bool onEnabled(Context* context);