diff --git a/include/imodelsurface.h b/include/imodelsurface.h
index 3e5d02b5d2..6cabb7809a 100644
--- a/include/imodelsurface.h
+++ b/include/imodelsurface.h
@@ -3,6 +3,8 @@
 // Math/Vertex classes
 #include "render/MeshVertex.h"
 
+class AABB;
+
 namespace model
 {
 
diff --git a/libs/wxutil/dialog/DialogBase.h b/libs/wxutil/dialog/DialogBase.h
index 00459cb31f..e52b79e540 100644
--- a/libs/wxutil/dialog/DialogBase.h
+++ b/libs/wxutil/dialog/DialogBase.h
@@ -2,6 +2,7 @@
 
 #include <string>
 #include <wx/dialog.h>
+#include <wx/frame.h>
 #include "../WindowPosition.h"
 #include "../WindowState.h"
 
diff --git a/radiant/ui/aas/RenderableAasFile.cpp b/radiant/ui/aas/RenderableAasFile.cpp
index 91a24f3df6..d260c6d7cb 100644
--- a/radiant/ui/aas/RenderableAasFile.cpp
+++ b/radiant/ui/aas/RenderableAasFile.cpp
@@ -1,5 +1,6 @@
 #include "RenderableAasFile.h"
 
+#include "imap.h"
 #include "iregistry.h"
 #include "ui/imainframe.h"
 #include "ivolumetest.h"
diff --git a/radiant/ui/common/ImageFileSelector.cpp b/radiant/ui/common/ImageFileSelector.cpp
index beeb3cd633..78ab4a98f5 100644
--- a/radiant/ui/common/ImageFileSelector.cpp
+++ b/radiant/ui/common/ImageFileSelector.cpp
@@ -3,6 +3,7 @@
 #include "i18n.h"
 #include "ImageFilePopulator.h"
 #include "wxutil/dataview/ResourceTreeViewToolbar.h"
+#include <wx/sizer.h>
 
 namespace ui
 {
diff --git a/radiant/ui/common/SoundShaderSelector.h b/radiant/ui/common/SoundShaderSelector.h
index 4bc21d2c4f..f472a2cbc4 100644
--- a/radiant/ui/common/SoundShaderSelector.h
+++ b/radiant/ui/common/SoundShaderSelector.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include "isound.h"
 #include "wxutil/decl/DeclarationSelector.h"
 #include "SoundShaderPreview.h"
 
diff --git a/radiant/ui/einspector/FxPropertyEditor.cpp b/radiant/ui/einspector/FxPropertyEditor.cpp
index 3eb3ca1110..53f2101a78 100644
--- a/radiant/ui/einspector/FxPropertyEditor.cpp
+++ b/radiant/ui/einspector/FxPropertyEditor.cpp
@@ -1,9 +1,17 @@
 #include "FxPropertyEditor.h"
 
+#include "i18n.h"
+#include "icommandsystem.h"
+#include "ientity.h"
+
 #include "ClassnamePropertyEditor.h"
 #include "PropertyEditorFactory.h"
 #include "ui/fx/FxChooser.h"
 
+#include <wx/sizer.h>
+#include <wx/panel.h>
+#include <wx/button.h>
+
 namespace ui
 {
 
diff --git a/radiant/ui/fx/FxChooser.cpp b/radiant/ui/fx/FxChooser.cpp
index 0dcb7c8c2e..8b6418dd27 100644
--- a/radiant/ui/fx/FxChooser.cpp
+++ b/radiant/ui/fx/FxChooser.cpp
@@ -1,5 +1,6 @@
 #include "FxChooser.h"
 
+#include "i18n.h"
 #include "debugging/ScopedDebugTimer.h"
 #include "os/path.h"
 #include "wxutil/dataview/ThreadedDeclarationTreePopulator.h"
diff --git a/radiant/ui/layers/LayerControlDialog.cpp b/radiant/ui/layers/LayerControlDialog.cpp
index bbc96450cc..7bf91f844e 100644
--- a/radiant/ui/layers/LayerControlDialog.cpp
+++ b/radiant/ui/layers/LayerControlDialog.cpp
@@ -1,11 +1,13 @@
 #include "LayerControlDialog.h"
 
 #include "i18n.h"
+#include "iregistry.h"
 #include "itextstream.h"
 #include "ilayer.h"
 #include "ui/imainframe.h"
 #include "iselection.h"
 
+#include <wx/bmpbuttn.h>
 #include <wx/button.h>
 #include <wx/tglbtn.h>
 #include <wx/sizer.h>
diff --git a/radiant/ui/layers/LayerControlDialog.h b/radiant/ui/layers/LayerControlDialog.h
index 2f394b7421..3b84445a47 100644
--- a/radiant/ui/layers/LayerControlDialog.h
+++ b/radiant/ui/layers/LayerControlDialog.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <map>
 #include "imap.h"
 #include "icommandsystem.h"
 #include "wxutil/window/TransientWindow.h"
diff --git a/radiant/ui/mainframe/TopLevelFrame.cpp b/radiant/ui/mainframe/TopLevelFrame.cpp
index ac811b80d6..b090117eef 100644
--- a/radiant/ui/mainframe/TopLevelFrame.cpp
+++ b/radiant/ui/mainframe/TopLevelFrame.cpp
@@ -10,6 +10,7 @@
 #include <wx/toolbar.h>
 #include <wx/menu.h>
 #include <wx/app.h>
+#include <wx/stattext.h>
 
 namespace ui
 {
diff --git a/radiant/ui/prefabselector/PrefabSelector.cpp b/radiant/ui/prefabselector/PrefabSelector.cpp
index 9e15688c8b..5851e7e6a0 100644
--- a/radiant/ui/prefabselector/PrefabSelector.cpp
+++ b/radiant/ui/prefabselector/PrefabSelector.cpp
@@ -3,6 +3,7 @@
 #include "ifilesystem.h"
 #include "ifiletypes.h"
 #include "itextstream.h"
+#include "ui/imainframe.h"
 #include "i18n.h"
 #include "iradiant.h"
 #include "imap.h"
diff --git a/radiantcore/brush/RenderableBrushVertices.h b/radiantcore/brush/RenderableBrushVertices.h
index 65a9cb257d..1ed9b37fc1 100644
--- a/radiantcore/brush/RenderableBrushVertices.h
+++ b/radiantcore/brush/RenderableBrushVertices.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include "iselection.h"
 #include "render/VertexCb.h"
 #include "render/RenderableGeometry.h"
 
diff --git a/radiantcore/decl/DeclarationFile.h b/radiantcore/decl/DeclarationFile.h
index ff1d9de673..422080b47c 100644
--- a/radiantcore/decl/DeclarationFile.h
+++ b/radiantcore/decl/DeclarationFile.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <string>
+#include <vector>
 #include "idecltypes.h"
 
 namespace decl
diff --git a/radiantcore/decl/DeclarationFolderParser.h b/radiantcore/decl/DeclarationFolderParser.h
index 8ea4570760..907224f3e1 100644
--- a/radiantcore/decl/DeclarationFolderParser.h
+++ b/radiantcore/decl/DeclarationFolderParser.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#include <map>
+#include "ideclmanager.h"
 #include "DeclarationFile.h"
 
 #include "parser/ThreadedDeclParser.h"
diff --git a/radiantcore/entity/AngleKey.h b/radiantcore/entity/AngleKey.h
index c26201a262..9fc18211f9 100644
--- a/radiantcore/entity/AngleKey.h
+++ b/radiantcore/entity/AngleKey.h
@@ -2,6 +2,7 @@
 
 #include "math/Quaternion.h"
 #include "math/FloatTools.h"
+#include <sigc++/trackable.h>
 #include <functional>
 
 class Entity;
diff --git a/radiantcore/entity/ModelKey.cpp b/radiantcore/entity/ModelKey.cpp
index 2207fe7c3c..de6cf09595 100644
--- a/radiantcore/entity/ModelKey.cpp
+++ b/radiantcore/entity/ModelKey.cpp
@@ -2,6 +2,7 @@
 
 #include <functional>
 #include "imodelcache.h"
+#include "imd5model.h"
 #include "ifilter.h"
 #include "modelskin.h"
 #include "string/replace.h"
diff --git a/radiantcore/entity/ModelKey.h b/radiantcore/entity/ModelKey.h
index e11f2be5a0..e7862ebebf 100644
--- a/radiantcore/entity/ModelKey.h
+++ b/radiantcore/entity/ModelKey.h
@@ -2,6 +2,7 @@
 
 #include <string>
 #include "inode.h"
+#include "ieclass.h"
 #include "ObservedUndoable.h"
 #include <sigc++/connection.h>
 
diff --git a/radiantcore/entity/RenderableEntityBox.h b/radiantcore/entity/RenderableEntityBox.h
index 2ec82751e4..c574f31faa 100644
--- a/radiantcore/entity/RenderableEntityBox.h
+++ b/radiantcore/entity/RenderableEntityBox.h
@@ -2,11 +2,11 @@
 
 #include "render/RenderableBox.h"
 
+class IEntityNode;
+
 namespace entity
 {
 
-class EntityNode;
-
 class RenderableEntityBox final :
     public render::RenderableBox
 {
diff --git a/radiantcore/entity/light/LightNode.cpp b/radiantcore/entity/light/LightNode.cpp
index e5260ed35b..c5b74bb61b 100644
--- a/radiantcore/entity/light/LightNode.cpp
+++ b/radiantcore/entity/light/LightNode.cpp
@@ -1,5 +1,6 @@
 #include "LightNode.h"
 
+#include "igrid.h"
 #include "ishaders.h"
 #include "icolourscheme.h"
 #include "../EntitySettings.h"
diff --git a/radiantcore/entity/speaker/SpeakerRenderables.cpp b/radiantcore/entity/speaker/SpeakerRenderables.cpp
index 7c9230693d..22edf94cfb 100644
--- a/radiantcore/entity/speaker/SpeakerRenderables.cpp
+++ b/radiantcore/entity/speaker/SpeakerRenderables.cpp
@@ -1,5 +1,6 @@
 #include "SpeakerRenderables.h"
 
+#include "ientity.h"
 #include "render.h"
 
 namespace entity
diff --git a/radiantcore/entity/speaker/SpeakerRenderables.h b/radiantcore/entity/speaker/SpeakerRenderables.h
index fa9093cc0e..ee169d7a42 100644
--- a/radiantcore/entity/speaker/SpeakerRenderables.h
+++ b/radiantcore/entity/speaker/SpeakerRenderables.h
@@ -4,6 +4,8 @@
 #include "math/Vector3.h"
 #include "render/RenderableGeometry.h"
 
+class IEntityNode;
+
 namespace entity
 {
 
diff --git a/radiantcore/entity/target/RenderableTargetLines.h b/radiantcore/entity/target/RenderableTargetLines.h
index d43adeb422..10fd10b714 100644
--- a/radiantcore/entity/target/RenderableTargetLines.h
+++ b/radiantcore/entity/target/RenderableTargetLines.h
@@ -2,6 +2,7 @@
 
 #include "TargetKeyCollection.h"
 #include "render.h"
+#include "ientity.h"
 #include "irenderable.h"
 #include "ivolumetest.h"
 #include "math/Segment.h"
diff --git a/radiantcore/fonts/FontLoader.cpp b/radiantcore/fonts/FontLoader.cpp
index f9759d2b7e..5fb758ee97 100644
--- a/radiantcore/fonts/FontLoader.cpp
+++ b/radiantcore/fonts/FontLoader.cpp
@@ -5,6 +5,7 @@
 
 #include <regex>
 
+#include "igame.h" 
 #include "ifilesystem.h"
 #include "itextstream.h"
 #include "FontManager.h"
diff --git a/radiantcore/fx/FxAction.cpp b/radiantcore/fx/FxAction.cpp
index ce21149a41..7c50468530 100644
--- a/radiantcore/fx/FxAction.cpp
+++ b/radiantcore/fx/FxAction.cpp
@@ -1,6 +1,6 @@
 #include "FxAction.h"
 
-#include "parser/DefTokeniser.h"
+#include "string/convert.h"
 #include "string/case_conv.h"
 #include "FxDeclaration.h"
 
diff --git a/radiantcore/fx/FxAction.h b/radiantcore/fx/FxAction.h
index 34a0ee5765..c594581881 100644
--- a/radiantcore/fx/FxAction.h
+++ b/radiantcore/fx/FxAction.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "ifx.h"
+#include "parser/DefTokeniser.h"
 
 namespace fx
 {
diff --git a/radiantcore/map/algorithm/Export.cpp b/radiantcore/map/algorithm/Export.cpp
index 13fa540009..c6b79d7fa9 100644
--- a/radiantcore/map/algorithm/Export.cpp
+++ b/radiantcore/map/algorithm/Export.cpp
@@ -2,6 +2,7 @@
 
 #include <stdexcept>
 #include "i18n.h"
+#include "ieclass.h"
 #include "ifilesystem.h"
 #include "imodelcache.h"
 #include "ientity.h"
diff --git a/radiantcore/model/NullModelNode.h b/radiantcore/model/NullModelNode.h
index 4f552356bb..de7361ba8b 100644
--- a/radiantcore/model/NullModelNode.h
+++ b/radiantcore/model/NullModelNode.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "Bounded.h"
+#include "iselectiontest.h"
 #include "irenderable.h"
 
 #include "scene/Node.h"
diff --git a/radiantcore/model/export/PatchSurface.h b/radiantcore/model/export/PatchSurface.h
index 58797336bb..467b989a47 100644
--- a/radiantcore/model/export/PatchSurface.h
+++ b/radiantcore/model/export/PatchSurface.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "ipatch.h"
+#include "math/AABB.h"
 #include "imodelsurface.h"
 
 namespace model
diff --git a/radiantcore/rendersystem/backend/GLProgramFactory.cpp b/radiantcore/rendersystem/backend/GLProgramFactory.cpp
index 5c0de2b152..fa744cf8b5 100644
--- a/radiantcore/rendersystem/backend/GLProgramFactory.cpp
+++ b/radiantcore/rendersystem/backend/GLProgramFactory.cpp
@@ -8,6 +8,7 @@
 #include "glprogram/RegularStageProgram.h"
 #include "glprogram/BlendLightProgram.h"
 
+#include "irender.h"
 #include "itextstream.h"
 #include "iregistry.h"
 #include "imodule.h"
diff --git a/radiantcore/rendersystem/backend/GLProgramFactory.h b/radiantcore/rendersystem/backend/GLProgramFactory.h
index eb9c1d50f5..8ad3ad710c 100644
--- a/radiantcore/rendersystem/backend/GLProgramFactory.h
+++ b/radiantcore/rendersystem/backend/GLProgramFactory.h
@@ -3,6 +3,7 @@
 #include <map>
 #include <memory>
 #include "igl.h"
+#include "iglprogram.h"
 
 namespace render
 {
diff --git a/radiantcore/rendersystem/backend/ObjectRenderer.cpp b/radiantcore/rendersystem/backend/ObjectRenderer.cpp
index f2d0b44138..831c367bd4 100644
--- a/radiantcore/rendersystem/backend/ObjectRenderer.cpp
+++ b/radiantcore/rendersystem/backend/ObjectRenderer.cpp
@@ -1,5 +1,7 @@
 #include "ObjectRenderer.h"
 
+#include "GLProgramAttributes.h"
+#include "irenderableobject.h"
 #include "math/Matrix4.h"
 #include "render/RenderVertex.h"
 
diff --git a/radiantcore/rendersystem/backend/OpenGLState.h b/radiantcore/rendersystem/backend/OpenGLState.h
index d1691caa4c..55b1194d43 100644
--- a/radiantcore/rendersystem/backend/OpenGLState.h
+++ b/radiantcore/rendersystem/backend/OpenGLState.h
@@ -1,15 +1,14 @@
 #pragma once
 
 #include "igl.h"
+#include "iglprogram.h"
 #include "ishaders.h"
 #include "ishaderlayer.h"
+#include "irender.h"
 
 #include "debugging/gl.h"
 #include "render/Colour4.h"
 
-// Full declaration in iglprogram.h
-class GLProgram;
-
 namespace render
 {
 
diff --git a/radiantcore/rendersystem/backend/SceneRenderer.cpp b/radiantcore/rendersystem/backend/SceneRenderer.cpp
index 65faa9499f..cdbc0959d0 100644
--- a/radiantcore/rendersystem/backend/SceneRenderer.cpp
+++ b/radiantcore/rendersystem/backend/SceneRenderer.cpp
@@ -1,5 +1,6 @@
 #include "SceneRenderer.h"
 
+#include "GLProgramAttributes.h"
 #include "igl.h"
 #include "OpenGLState.h"
 
diff --git a/radiantcore/rendersystem/backend/glprogram/BlendLightProgram.cpp b/radiantcore/rendersystem/backend/glprogram/BlendLightProgram.cpp
index 3b7d8e0e62..803c2d1321 100644
--- a/radiantcore/rendersystem/backend/glprogram/BlendLightProgram.cpp
+++ b/radiantcore/rendersystem/backend/glprogram/BlendLightProgram.cpp
@@ -1,5 +1,6 @@
 #include "BlendLightProgram.h"
 
+#include "GLProgramAttributes.h"
 #include "debugging/gl.h"
 #include "rendersystem/backend/GLProgramFactory.h"
 
diff --git a/radiantcore/rendersystem/backend/glprogram/BlendLightProgram.h b/radiantcore/rendersystem/backend/glprogram/BlendLightProgram.h
index 175e7350cb..3ba6fec718 100644
--- a/radiantcore/rendersystem/backend/glprogram/BlendLightProgram.h
+++ b/radiantcore/rendersystem/backend/glprogram/BlendLightProgram.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "GLSLProgramBase.h"
+#include "render/Colour4.h"
 
 namespace render
 {
diff --git a/radiantcore/rendersystem/backend/glprogram/CubeMapProgram.cpp b/radiantcore/rendersystem/backend/glprogram/CubeMapProgram.cpp
index 33dcbd4b02..4fffd59524 100644
--- a/radiantcore/rendersystem/backend/glprogram/CubeMapProgram.cpp
+++ b/radiantcore/rendersystem/backend/glprogram/CubeMapProgram.cpp
@@ -1,6 +1,7 @@
 #include "CubeMapProgram.h"
 
 #include "itextstream.h"
+#include "GLProgramAttributes.h"
 #include "debugging/gl.h"
 #include "igl.h"
 #include "../GLProgramFactory.h"
diff --git a/radiantcore/rendersystem/backend/glprogram/CubeMapProgram.h b/radiantcore/rendersystem/backend/glprogram/CubeMapProgram.h
index 38f5e787d5..fd22270ae8 100644
--- a/radiantcore/rendersystem/backend/glprogram/CubeMapProgram.h
+++ b/radiantcore/rendersystem/backend/glprogram/CubeMapProgram.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "GLSLProgramBase.h"
+#include "math/Vector3.h"
 
 namespace render
 {
diff --git a/radiantcore/rendersystem/backend/glprogram/GLSLProgramBase.h b/radiantcore/rendersystem/backend/glprogram/GLSLProgramBase.h
index 4dbb105561..91114bc674 100644
--- a/radiantcore/rendersystem/backend/glprogram/GLSLProgramBase.h
+++ b/radiantcore/rendersystem/backend/glprogram/GLSLProgramBase.h
@@ -2,6 +2,7 @@
 
 #include "iglprogram.h"
 #include "igl.h"
+#include "math/Matrix4.h"
 
 namespace render
 {
diff --git a/radiantcore/rendersystem/backend/glprogram/InteractionProgram.h b/radiantcore/rendersystem/backend/glprogram/InteractionProgram.h
index a68880b79a..126b6567f8 100644
--- a/radiantcore/rendersystem/backend/glprogram/InteractionProgram.h
+++ b/radiantcore/rendersystem/backend/glprogram/InteractionProgram.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#include "ishaderlayer.h"
+#include "irender.h"
 #include "GLSLProgramBase.h"
 
 namespace render
diff --git a/radiantcore/rendersystem/backend/glprogram/RegularStageProgram.cpp b/radiantcore/rendersystem/backend/glprogram/RegularStageProgram.cpp
index 2ce1c9b7ce..109f240e2d 100644
--- a/radiantcore/rendersystem/backend/glprogram/RegularStageProgram.cpp
+++ b/radiantcore/rendersystem/backend/glprogram/RegularStageProgram.cpp
@@ -1,6 +1,7 @@
 #include "RegularStageProgram.h"
 
 #include "itextstream.h"
+#include "GLProgramAttributes.h"
 #include "debugging/gl.h"
 #include "igl.h"
 #include "../GLProgramFactory.h"
diff --git a/radiantcore/rendersystem/backend/glprogram/RegularStageProgram.h b/radiantcore/rendersystem/backend/glprogram/RegularStageProgram.h
index 1854d561d7..b26064411f 100644
--- a/radiantcore/rendersystem/backend/glprogram/RegularStageProgram.h
+++ b/radiantcore/rendersystem/backend/glprogram/RegularStageProgram.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include "ishaderlayer.h"
 #include "GLSLProgramBase.h"
 
 namespace render