diff --git a/apps/openmw/mwbase/inputmanager.hpp b/apps/openmw/mwbase/inputmanager.hpp
index 373182fb5b..2861ab88e9 100644
--- a/apps/openmw/mwbase/inputmanager.hpp
+++ b/apps/openmw/mwbase/inputmanager.hpp
@@ -5,7 +5,6 @@
 #include <string>
 #include <vector>
 
-#include <MyGUI_Widget.h>
 #include <SDL_gamecontroller.h>
 #include <cstdint>
 
@@ -20,6 +19,11 @@ namespace ESM
     class ESMWriter;
 }
 
+namespace MyGUI
+{
+    class Widget;
+}
+
 namespace MWBase
 {
     /// \brief Interface for input manager (implemented in MWInput)
diff --git a/apps/openmw/mwbase/windowmanager.hpp b/apps/openmw/mwbase/windowmanager.hpp
index b7380e6442..a610a66c57 100644
--- a/apps/openmw/mwbase/windowmanager.hpp
+++ b/apps/openmw/mwbase/windowmanager.hpp
@@ -11,10 +11,9 @@
 
 #include <MyGUI_KeyCode.h>
 
-#include "../mwgui/hud.hpp"
 #include "../mwgui/mode.hpp"
-#include "../mwgui/windowbase.hpp"
 
+#include <components/esm/refid.hpp>
 #include <components/sdlutil/events.hpp>
 
 namespace ESM
@@ -80,6 +79,8 @@ namespace MWGui
     class MessageBox;
     class PostProcessorHud;
     class SettingsWindow;
+    class HUD;
+    class WindowBase;
 
     enum ShowInDialogueMode
     {
diff --git a/apps/openmw/mwgui/companionwindow.hpp b/apps/openmw/mwgui/companionwindow.hpp
index 986b75255c..1b5a772684 100644
--- a/apps/openmw/mwgui/companionwindow.hpp
+++ b/apps/openmw/mwgui/companionwindow.hpp
@@ -1,8 +1,6 @@
 #ifndef OPENMW_MWGUI_COMPANIONWINDOW_H
 #define OPENMW_MWGUI_COMPANIONWINDOW_H
 
-#include "companionitemmodel.hpp"
-#include "itemmodel.hpp"
 #include "referenceinterface.hpp"
 #include "windowbase.hpp"
 
@@ -46,7 +44,7 @@ namespace MWGui
         void setActiveControllerWindow(bool active) override;
 
         MWGui::ItemView* getItemView() { return mItemView; }
-        ItemModel* getModel() { return mModel; }
+        CompanionItemModel* getModel() { return mModel; }
 
     private:
         ItemView* mItemView;
diff --git a/apps/openmw/mwgui/countdialog.cpp b/apps/openmw/mwgui/countdialog.cpp
index db34b082e0..43c5bfe5da 100644
--- a/apps/openmw/mwgui/countdialog.cpp
+++ b/apps/openmw/mwgui/countdialog.cpp
@@ -5,6 +5,7 @@
 #include <MyGUI_ScrollBar.h>
 
 #include <components/widgets/numericeditbox.hpp>
+#include <components/widgets/scrollbar.hpp>
 
 #include "../mwbase/environment.hpp"
 #include "../mwbase/windowmanager.hpp"
diff --git a/apps/openmw/mwgui/countdialog.hpp b/apps/openmw/mwgui/countdialog.hpp
index e31c2419b8..8f0bbc7caf 100644
--- a/apps/openmw/mwgui/countdialog.hpp
+++ b/apps/openmw/mwgui/countdialog.hpp
@@ -3,11 +3,10 @@
 
 #include "windowbase.hpp"
 
-#include <components/widgets/scrollbar.hpp>
-
 namespace Gui
 {
     class NumericEditBox;
+    class ScrollBar;
 }
 
 namespace MWGui
diff --git a/apps/openmw/mwgui/inventorytabsoverlay.cpp b/apps/openmw/mwgui/inventorytabsoverlay.cpp
index fb9c7dec3d..7464a3b1ec 100644
--- a/apps/openmw/mwgui/inventorytabsoverlay.cpp
+++ b/apps/openmw/mwgui/inventorytabsoverlay.cpp
@@ -1,5 +1,6 @@
 #include "inventorytabsoverlay.hpp"
 
+#include <MyGUI_Button.h>
 #include <MyGUI_ImageBox.h>
 #include <MyGUI_Window.h>
 
diff --git a/apps/openmw/mwgui/inventorytabsoverlay.hpp b/apps/openmw/mwgui/inventorytabsoverlay.hpp
index 1f5cf39607..26544aa310 100644
--- a/apps/openmw/mwgui/inventorytabsoverlay.hpp
+++ b/apps/openmw/mwgui/inventorytabsoverlay.hpp
@@ -1,10 +1,13 @@
 #ifndef MWGUI_INVENTORYTABSSOVERLAY_H
 #define MWGUI_INVENTORYTABSSOVERLAY_H
 
-#include <MyGUI_Button.h>
-
 #include "windowbase.hpp"
 
+namespace MyGUI
+{
+    class Button;
+}
+
 namespace MWGui
 {
     class InventoryTabsOverlay : public WindowBase
diff --git a/apps/openmw/mwgui/itemchargeview.cpp b/apps/openmw/mwgui/itemchargeview.cpp
index 31b29122f3..f7e7f71e3d 100644
--- a/apps/openmw/mwgui/itemchargeview.cpp
+++ b/apps/openmw/mwgui/itemchargeview.cpp
@@ -24,6 +24,7 @@
 #include "itemmodel.hpp"
 #include "itemwidget.hpp"
 #include "textcolours.hpp"
+#include "windowbase.hpp"
 
 namespace MWGui
 {
diff --git a/apps/openmw/mwgui/itemview.hpp b/apps/openmw/mwgui/itemview.hpp
index e032fe3ec3..6243618abc 100644
--- a/apps/openmw/mwgui/itemview.hpp
+++ b/apps/openmw/mwgui/itemview.hpp
@@ -2,7 +2,6 @@
 #define MWGUI_ITEMVIEW_H
 
 #include <MyGUI_Widget.h>
-#include <SDL.h>
 
 #include "itemmodel.hpp"
 
diff --git a/apps/openmw/mwgui/quickkeysmenu.cpp b/apps/openmw/mwgui/quickkeysmenu.cpp
index 23601c1b53..8aacc6f148 100644
--- a/apps/openmw/mwgui/quickkeysmenu.cpp
+++ b/apps/openmw/mwgui/quickkeysmenu.cpp
@@ -11,6 +11,7 @@
 #include <components/esm3/quickkeys.hpp>
 #include <components/misc/resourcehelpers.hpp>
 #include <components/resource/resourcesystem.hpp>
+#include <components/settings/values.hpp>
 
 #include "../mwworld/class.hpp"
 #include "../mwworld/esmstore.hpp"
diff --git a/apps/openmw/mwgui/race.cpp b/apps/openmw/mwgui/race.cpp
index f1843fb4d7..e31f31c8be 100644
--- a/apps/openmw/mwgui/race.cpp
+++ b/apps/openmw/mwgui/race.cpp
@@ -13,6 +13,7 @@
 #include <components/esm3/loadrace.hpp>
 #include <components/myguiplatform/myguitexture.hpp>
 #include <components/settings/values.hpp>
+#include <components/widgets/scrollbar.hpp>
 
 #include "../mwbase/environment.hpp"
 #include "../mwbase/windowmanager.hpp"
diff --git a/apps/openmw/mwgui/race.hpp b/apps/openmw/mwgui/race.hpp
index ead058214c..1f6400e5b2 100644
--- a/apps/openmw/mwgui/race.hpp
+++ b/apps/openmw/mwgui/race.hpp
@@ -3,7 +3,6 @@
 
 #include "windowbase.hpp"
 #include <components/esm/refid.hpp>
-#include <components/widgets/scrollbar.hpp>
 #include <memory>
 
 namespace MWRender
@@ -26,6 +25,11 @@ namespace Resource
     class ResourceSystem;
 }
 
+namespace Gui
+{
+    class ScrollBar;
+}
+
 namespace MWGui
 {
     class RaceDialog : public WindowModal
diff --git a/apps/openmw/mwgui/spellcreationdialog.cpp b/apps/openmw/mwgui/spellcreationdialog.cpp
index 190793b77a..49a71801aa 100644
--- a/apps/openmw/mwgui/spellcreationdialog.cpp
+++ b/apps/openmw/mwgui/spellcreationdialog.cpp
@@ -9,6 +9,7 @@
 #include <components/resource/resourcesystem.hpp>
 #include <components/settings/values.hpp>
 #include <components/widgets/list.hpp>
+#include <components/widgets/scrollbar.hpp>
 
 #include <components/esm3/loadgmst.hpp>
 
diff --git a/apps/openmw/mwgui/spellcreationdialog.hpp b/apps/openmw/mwgui/spellcreationdialog.hpp
index 2a4f5dcbb3..35e3fb2eb2 100644
--- a/apps/openmw/mwgui/spellcreationdialog.hpp
+++ b/apps/openmw/mwgui/spellcreationdialog.hpp
@@ -1,12 +1,10 @@
 #ifndef MWGUI_SPELLCREATION_H
 #define MWGUI_SPELLCREATION_H
 
-#include <SDL.h>
 #include <memory>
 
 #include <components/esm3/loadmgef.hpp>
 #include <components/esm3/loadspel.hpp>
-#include <components/widgets/scrollbar.hpp>
 
 #include "referenceinterface.hpp"
 #include "widgets.hpp"
@@ -15,6 +13,7 @@
 namespace Gui
 {
     class MWList;
+    class ScrollBar;
 }
 
 namespace MWGui
diff --git a/apps/openmw/mwgui/spellview.cpp b/apps/openmw/mwgui/spellview.cpp
index 6ae757b7be..ee1755e706 100644
--- a/apps/openmw/mwgui/spellview.cpp
+++ b/apps/openmw/mwgui/spellview.cpp
@@ -14,6 +14,7 @@
 #include "../mwbase/windowmanager.hpp"
 
 #include "tooltips.hpp"
+#include "windowbase.hpp"
 
 namespace MWGui
 {
diff --git a/apps/openmw/mwgui/spellview.hpp b/apps/openmw/mwgui/spellview.hpp
index a2571cd822..7895b86ec8 100644
--- a/apps/openmw/mwgui/spellview.hpp
+++ b/apps/openmw/mwgui/spellview.hpp
@@ -5,9 +5,6 @@
 #include <tuple>
 
 #include <MyGUI_Widget.h>
-#include <SDL.h>
-
-#include <components/widgets/sharedstatebutton.hpp>
 
 #include "spellmodel.hpp"
 
@@ -16,6 +13,11 @@ namespace MyGUI
     class ScrollView;
 }
 
+namespace Gui
+{
+    class SharedStateButton;
+}
+
 namespace MWGui
 {
 
diff --git a/apps/openmw/mwgui/waitdialog.cpp b/apps/openmw/mwgui/waitdialog.cpp
index 0943863a69..0a4d4a6ffc 100644
--- a/apps/openmw/mwgui/waitdialog.cpp
+++ b/apps/openmw/mwgui/waitdialog.cpp
@@ -10,6 +10,7 @@
 #include <components/misc/strings/format.hpp>
 #include <components/settings/values.hpp>
 #include <components/widgets/box.hpp>
+#include <components/widgets/scrollbar.hpp>
 
 #include "../mwbase/environment.hpp"
 #include "../mwbase/mechanicsmanager.hpp"
diff --git a/apps/openmw/mwgui/waitdialog.hpp b/apps/openmw/mwgui/waitdialog.hpp
index 4a7ccfcd00..c3dc45587c 100644
--- a/apps/openmw/mwgui/waitdialog.hpp
+++ b/apps/openmw/mwgui/waitdialog.hpp
@@ -4,7 +4,11 @@
 #include "timeadvancer.hpp"
 #include "windowbase.hpp"
 #include <components/esm/refid.hpp>
-#include <components/widgets/scrollbar.hpp>
+
+namespace Gui
+{
+    class ScrollBar;
+}
 
 namespace MWGui
 {
diff --git a/apps/openmw/mwgui/windowbase.hpp b/apps/openmw/mwgui/windowbase.hpp
index fb88af499a..e4b4636246 100644
--- a/apps/openmw/mwgui/windowbase.hpp
+++ b/apps/openmw/mwgui/windowbase.hpp
@@ -1,7 +1,7 @@
 #ifndef MWGUI_WINDOW_BASE_H
 #define MWGUI_WINDOW_BASE_H
 
-#include <SDL.h>
+#include <SDL_events.h>
 
 #include "layout.hpp"
 
diff --git a/apps/openmw/mwgui/windowmanagerimp.cpp b/apps/openmw/mwgui/windowmanagerimp.cpp
index c5804a7858..bcc67e42c1 100644
--- a/apps/openmw/mwgui/windowmanagerimp.cpp
+++ b/apps/openmw/mwgui/windowmanagerimp.cpp
@@ -83,6 +83,7 @@
 #include "confirmationdialog.hpp"
 #include "console.hpp"
 #include "container.hpp"
+#include "controllerbuttonsoverlay.hpp"
 #include "controllers.hpp"
 #include "countdialog.hpp"
 #include "cursor.hpp"
@@ -91,6 +92,7 @@
 #include "enchantingdialog.hpp"
 #include "exposedwindow.hpp"
 #include "hud.hpp"
+#include "inventorytabsoverlay.hpp"
 #include "inventorywindow.hpp"
 #include "itemchargeview.hpp"
 #include "itemtransfer.hpp"
diff --git a/apps/openmw/mwgui/windowmanagerimp.hpp b/apps/openmw/mwgui/windowmanagerimp.hpp
index 06360dd9f2..211ce60dca 100644
--- a/apps/openmw/mwgui/windowmanagerimp.hpp
+++ b/apps/openmw/mwgui/windowmanagerimp.hpp
@@ -24,9 +24,7 @@
 #include <components/toutf8/toutf8.hpp>
 
 #include "charactercreation.hpp"
-#include "controllerbuttonsoverlay.hpp"
 #include "draganddrop.hpp"
-#include "inventorytabsoverlay.hpp"
 #include "mapwindow.hpp"
 #include "messagebox.hpp"
 #include "settings.hpp"
@@ -47,6 +45,8 @@ namespace MyGUI
     class Window;
     class UString;
     class ImageBox;
+    class ControllerButtonsOverlay;
+    class InventoryTabsOverlay;
 }
 
 namespace MWWorld