diff --git a/source/gui/CButton.h b/source/gui/CButton.h
index 3f7be17596..9354bc84ca 100644
--- a/source/gui/CButton.h
+++ b/source/gui/CButton.h
@@ -18,14 +18,10 @@
 #ifndef INCLUDED_CBUTTON
 #define INCLUDED_CBUTTON
 
-#include "GUI.h"
+#include "gui/IGUIButtonBehavior.h"
+#include "gui/IGUIObject.h"
+#include "gui/IGUITextOwner.h"
 
-/**
- * Button
- *
- * @see IGUIObject
- * @see IGUIButtonBehavior
- */
 class CButton : public IGUIButtonBehavior, public IGUITextOwner
 {
 	GUI_OBJECT(CButton)
diff --git a/source/gui/CChart.cpp b/source/gui/CChart.cpp
index bdfa0e0655..29b9233092 100644
--- a/source/gui/CChart.cpp
+++ b/source/gui/CChart.cpp
@@ -20,6 +20,8 @@
 #include "CChart.h"
 
 #include "gui/CGUIColor.h"
+#include "gui/CGUIList.h"
+#include "gui/CGUISeries.h"
 #include "gui/CGUIString.h"
 #include "gui/GUIMatrix.h"
 #include "graphics/ShaderManager.h"
diff --git a/source/gui/CChart.h b/source/gui/CChart.h
index de0c0fc3f1..5d3114dd14 100644
--- a/source/gui/CChart.h
+++ b/source/gui/CChart.h
@@ -18,13 +18,11 @@
 #ifndef INCLUDED_CCHART
 #define INCLUDED_CCHART
 
-#include "gui/GUI.h"
 #include "gui/IGUITextOwner.h"
 #include "maths/Vector2D.h"
 
 #include <vector>
 
-
 struct CChartData
 {
 	// Avoid copying the container.
@@ -38,8 +36,6 @@ struct CChartData
 
 /**
  * Chart for a data visualization as lines or points
- *
- * @see IGUIObject
  */
 class CChart : public IGUITextOwner
 {
diff --git a/source/gui/CCheckBox.h b/source/gui/CCheckBox.h
index a4c2062265..c1fd763148 100644
--- a/source/gui/CCheckBox.h
+++ b/source/gui/CCheckBox.h
@@ -18,15 +18,10 @@
 #ifndef INCLUDED_CCHECKBOX
 #define INCLUDED_CCHECKBOX
 
-#include "GUI.h"
+#include "gui/IGUIButtonBehavior.h"
+#include "gui/IGUIObject.h"
+#include "gui/IGUITextOwner.h"
 
-/**
- * CheckBox
- *
- * @see IGUIObject
- * @see IGUISettingsObject
- * @see IGUIButtonBehavior
- */
 class CCheckBox : public IGUIButtonBehavior, public IGUITextOwner
 {
 	GUI_OBJECT(CCheckBox)
diff --git a/source/gui/CDropDown.h b/source/gui/CDropDown.h
index 99d82b5666..007e70b469 100644
--- a/source/gui/CDropDown.h
+++ b/source/gui/CDropDown.h
@@ -23,18 +23,16 @@ GUI Object - Drop Down (list)
 	Works just like a list-box, but it hides
 	all the elements that aren't selected. They
 	can be brought up by pressing the control.
-
---More info--
-
-	Check GUI.h
-
 */
 
 #ifndef INCLUDED_CDROPDOWN
 #define INCLUDED_CDROPDOWN
 
-#include "GUI.h"
-#include "CList.h"
+#include "gui/CGUIList.h"
+#include "gui/CList.h"
+#include "gui/IGUIScrollBar.h"
+
+#include <string>
 
 /**
  * Drop Down
diff --git a/source/gui/CGUI.h b/source/gui/CGUI.h
index 0f29f31f52..9000543f8d 100644
--- a/source/gui/CGUI.h
+++ b/source/gui/CGUI.h
@@ -32,6 +32,8 @@
 #include "scriptinterface/ScriptInterface.h"
 
 #include <boost/unordered_set.hpp>
+#include <map>
+#include <vector>
 
 ERROR_TYPE(GUI, JSOpenFailed);
 
diff --git a/source/gui/CGUIList.h b/source/gui/CGUIList.h
index 1f319a44d7..676c80324a 100644
--- a/source/gui/CGUIList.h
+++ b/source/gui/CGUIList.h
@@ -20,6 +20,8 @@
 
 #include "gui/CGUIString.h"
 
+#include <vector>
+
 class CGUIList
 {
 public: // struct:ish (but for consistency I call it _C_GUIList, and
diff --git a/source/gui/CGUIScrollBarVertical.cpp b/source/gui/CGUIScrollBarVertical.cpp
index 2d3a8ef6c1..385efa22c8 100644
--- a/source/gui/CGUIScrollBarVertical.cpp
+++ b/source/gui/CGUIScrollBarVertical.cpp
@@ -19,9 +19,7 @@
 
 #include "CGUIScrollBarVertical.h"
 
-#include "GUI.h"
-#include "CGUI.h"
-
+#include "gui/CGUI.h"
 #include "ps/CLogger.h"
 
 
diff --git a/source/gui/CGUIScrollBarVertical.h b/source/gui/CGUIScrollBarVertical.h
index 27ec948948..aaa545b337 100644
--- a/source/gui/CGUIScrollBarVertical.h
+++ b/source/gui/CGUIScrollBarVertical.h
@@ -16,29 +16,15 @@
  */
 
 /*
-A GUI ScrollBar
-
---Overview--
-
 	A GUI Scrollbar, this class doesn't present all functionality
 	to the scrollbar, it just controls the drawing and a wrapper
 	for interaction with it.
-
---Usage--
-
-	Used in everywhere scrollbars are needed, like in a combobox for instance.
-
---More info--
-
-	Check GUI.h
-
 */
 
 #ifndef INCLUDED_CGUISCROLLBARVERTICAL
 #define INCLUDED_CGUISCROLLBARVERTICAL
 
 #include "IGUIScrollBar.h"
-#include "GUI.h"
 
 /**
  * Vertical implementation of IGUIScrollBar
diff --git a/source/gui/CGUISeries.h b/source/gui/CGUISeries.h
index 05ce6243ae..259b607bfb 100644
--- a/source/gui/CGUISeries.h
+++ b/source/gui/CGUISeries.h
@@ -21,6 +21,8 @@
 
 #include "maths/Vector2D.h"
 
+#include <vector>
+
 class CGUISeries
 {
 public:
diff --git a/source/gui/CGUISetting.cpp b/source/gui/CGUISetting.cpp
index ebafe75027..ccb5d065ab 100644
--- a/source/gui/CGUISetting.cpp
+++ b/source/gui/CGUISetting.cpp
@@ -20,7 +20,6 @@
 #include "CGUISetting.h"
 
 #include "gui/CGUI.h"
-#include "gui/GUI.h"
 
 template<typename T>
 CGUISetting<T>::CGUISetting(IGUIObject& pObject, const CStr& Name)
diff --git a/source/gui/CGUISprite.h b/source/gui/CGUISprite.h
index d754ee0b87..4aa92b7bd3 100644
--- a/source/gui/CGUISprite.h
+++ b/source/gui/CGUISprite.h
@@ -28,7 +28,9 @@
 #include "gui/GUIRenderer.h"
 #include "lib/res/graphics/ogl_tex.h"
 
+#include <map>
 #include <memory>
+#include <vector>
 
 struct SGUIImageEffects
 {
diff --git a/source/gui/CGUIString.cpp b/source/gui/CGUIString.cpp
index 04941a6dfc..0cdc65b6b2 100644
--- a/source/gui/CGUIString.cpp
+++ b/source/gui/CGUIString.cpp
@@ -21,7 +21,6 @@
 
 #include "graphics/FontMetrics.h"
 #include "gui/CGUI.h"
-#include "gui/GUI.h"
 #include "lib/utf8.h"
 #include "ps/CLogger.h"
 
diff --git a/source/gui/CImage.cpp b/source/gui/CImage.cpp
index 5c0adfe752..dff3aae181 100644
--- a/source/gui/CImage.cpp
+++ b/source/gui/CImage.cpp
@@ -20,7 +20,6 @@
 #include "CImage.h"
 
 #include "gui/CGUI.h"
-#include "gui/GUI.h"
 #include "lib/ogl.h"
 
 CImage::CImage(CGUI& pGUI)
diff --git a/source/gui/CImage.h b/source/gui/CImage.h
index 58def04fc4..2b47a5f742 100644
--- a/source/gui/CImage.h
+++ b/source/gui/CImage.h
@@ -18,7 +18,7 @@
 #ifndef INCLUDED_CIMAGE
 #define INCLUDED_CIMAGE
 
-#include "GUI.h"
+#include "gui/IGUIObject.h"
 
 /**
  * Object just for drawing a sprite. Like CText, without the
@@ -29,8 +29,6 @@
  * without functionality used, and that is a lot of unnecessary
  * overhead. That's why I thought I'd go with an intuitive
  * control.
- *
- * @see IGUIObject
  */
 class CImage : public IGUIObject
 {
diff --git a/source/gui/CInput.cpp b/source/gui/CInput.cpp
index 8e16ea583e..9a69f1fd3e 100644
--- a/source/gui/CInput.cpp
+++ b/source/gui/CInput.cpp
@@ -21,7 +21,6 @@
 
 #include "gui/CGUI.h"
 #include "gui/CGUIScrollBarVertical.h"
-#include "gui/GUI.h"
 #include "graphics/FontMetrics.h"
 #include "graphics/ShaderManager.h"
 #include "graphics/TextRenderer.h"
diff --git a/source/gui/CInput.h b/source/gui/CInput.h
index 3639839980..ea302b3686 100644
--- a/source/gui/CInput.h
+++ b/source/gui/CInput.h
@@ -18,17 +18,17 @@
 #ifndef INCLUDED_CINPUT
 #define INCLUDED_CINPUT
 
-#include "GUI.h"
+#include "gui/IGUIScrollBarOwner.h"
 #include "lib/external_libraries/libsdl.h"
 
+#include <vector>
+
 /**
  * Text field where you can input and edit the text.
  *
  * It doesn't use IGUITextOwner, because we don't need
  * any other features than word-wrapping, and we need to be
  * able to rapidly change the string.
- *
- * @see IGUIObject
  */
 class CInput : public IGUIScrollBarOwner
 {
diff --git a/source/gui/CList.cpp b/source/gui/CList.cpp
index 32af716a55..d5b0052399 100644
--- a/source/gui/CList.cpp
+++ b/source/gui/CList.cpp
@@ -21,6 +21,7 @@
 
 #include "gui/CGUI.h"
 #include "gui/CGUIColor.h"
+#include "gui/CGUIList.h"
 #include "gui/CGUIScrollBarVertical.h"
 #include "lib/external_libraries/libsdl.h"
 #include "lib/timer.h"
diff --git a/source/gui/CList.h b/source/gui/CList.h
index 10b005be8b..a3d3f7283d 100644
--- a/source/gui/CList.h
+++ b/source/gui/CList.h
@@ -18,7 +18,10 @@
 #ifndef INCLUDED_CLIST
 #define INCLUDED_CLIST
 
-#include "IGUIScrollBar.h"
+#include "gui/IGUIScrollBarOwner.h"
+#include "gui/IGUITextOwner.h"
+
+#include <vector>
 
 /**
  * Create a list of elements, where one can be selected
diff --git a/source/gui/COList.cpp b/source/gui/COList.cpp
index 5397b41f23..9b617ed109 100644
--- a/source/gui/COList.cpp
+++ b/source/gui/COList.cpp
@@ -21,6 +21,8 @@
 
 #include "gui/CGUI.h"
 #include "gui/CGUIColor.h"
+#include "gui/CGUIList.h"
+#include "gui/IGUIScrollBar.h"
 #include "i18n/L10n.h"
 #include "ps/CLogger.h"
 
diff --git a/source/gui/COList.h b/source/gui/COList.h
index ca5acccfb6..0179b1333a 100644
--- a/source/gui/COList.h
+++ b/source/gui/COList.h
@@ -17,9 +17,10 @@
 #ifndef INCLUDED_COLIST
 #define INCLUDED_COLIST
 
-#include "GUI.h"
 #include "CList.h"
 
+#include <vector>
+
 /**
  * Represents a column.
  */
diff --git a/source/gui/CProgressBar.cpp b/source/gui/CProgressBar.cpp
index 3abc90adda..e0ff7e0e80 100644
--- a/source/gui/CProgressBar.cpp
+++ b/source/gui/CProgressBar.cpp
@@ -20,7 +20,6 @@
 #include "CProgressBar.h"
 
 #include "gui/CGUI.h"
-#include "gui/GUI.h"
 #include "lib/ogl.h"
 
 CProgressBar::CProgressBar(CGUI& pGUI)
diff --git a/source/gui/CProgressBar.h b/source/gui/CProgressBar.h
index 98621a2b78..490d879a81 100644
--- a/source/gui/CProgressBar.h
+++ b/source/gui/CProgressBar.h
@@ -18,12 +18,10 @@
 #ifndef INCLUDED_CPROGRESSBAR
 #define INCLUDED_CPROGRESSBAR
 
-#include "GUI.h"
+#include "gui/IGUIObject.h"
 
 /**
  * Object used to draw a value (e.g. progress) from 0 to 100 visually.
- *
- * @see IGUIObject
  */
 class CProgressBar : public IGUIObject
 {
diff --git a/source/gui/CRadioButton.cpp b/source/gui/CRadioButton.cpp
index 5c8d3fa9a3..1c8fa4b4ab 100644
--- a/source/gui/CRadioButton.cpp
+++ b/source/gui/CRadioButton.cpp
@@ -19,8 +19,6 @@
 
 #include "CRadioButton.h"
 
-#include "GUI.h"
-
 CRadioButton::CRadioButton(CGUI& pGUI)
 	: CCheckBox(pGUI), IGUIObject(pGUI)
 {
diff --git a/source/gui/CRadioButton.h b/source/gui/CRadioButton.h
index dc8f1e851c..cffc412b4c 100644
--- a/source/gui/CRadioButton.h
+++ b/source/gui/CRadioButton.h
@@ -18,7 +18,6 @@
 #ifndef INCLUDED_CRADIOBUTTON
 #define INCLUDED_CRADIOBUTTON
 
-#include "GUI.h"
 #include "CCheckBox.h"
 
 /**
diff --git a/source/gui/CSlider.cpp b/source/gui/CSlider.cpp
index 4b4a718330..6a70ede4b7 100644
--- a/source/gui/CSlider.cpp
+++ b/source/gui/CSlider.cpp
@@ -20,7 +20,6 @@
 #include "CSlider.h"
 
 #include "gui/CGUI.h"
-#include "gui/GUI.h"
 #include "lib/ogl.h"
 
 CSlider::CSlider(CGUI& pGUI)
diff --git a/source/gui/CSlider.h b/source/gui/CSlider.h
index 53179fdbc9..be9e63114e 100644
--- a/source/gui/CSlider.h
+++ b/source/gui/CSlider.h
@@ -18,8 +18,7 @@
 #ifndef INCLUDED_CSLIDER
 #define INCLUDED_CSLIDER
 
-#include "GUI.h"
-
+#include "gui/IGUIObject.h"
 
 class CSlider : public IGUIObject
 {
diff --git a/source/gui/CText.cpp b/source/gui/CText.cpp
index bff95cf8f4..6e60d60822 100644
--- a/source/gui/CText.cpp
+++ b/source/gui/CText.cpp
@@ -21,7 +21,6 @@
 
 #include "gui/CGUI.h"
 #include "gui/CGUIScrollBarVertical.h"
-#include "gui/GUI.h"
 #include "lib/ogl.h"
 
 CText::CText(CGUI& pGUI)
diff --git a/source/gui/CText.h b/source/gui/CText.h
index e838d5fd58..d3330602de 100644
--- a/source/gui/CText.h
+++ b/source/gui/CText.h
@@ -18,12 +18,11 @@
 #ifndef INCLUDED_CTEXT
 #define INCLUDED_CTEXT
 
-#include "GUI.h"
+#include "gui/IGUIScrollBarOwner.h"
+#include "gui/IGUITextOwner.h"
 
 /**
  * Text field that just displays static text.
- *
- * @see IGUIObject
  */
 class CText : public IGUIScrollBarOwner, public IGUITextOwner
 {
diff --git a/source/gui/CTooltip.cpp b/source/gui/CTooltip.cpp
index d1dbc00733..e8238ca15f 100644
--- a/source/gui/CTooltip.cpp
+++ b/source/gui/CTooltip.cpp
@@ -18,7 +18,8 @@
 #include "precompiled.h"
 
 #include "CTooltip.h"
-#include "CGUI.h"
+
+#include "gui/CGUI.h"
 
 #include <algorithm>
 
diff --git a/source/gui/GUI.h b/source/gui/GUI.h
deleted file mode 100644
index b96d34e948..0000000000
--- a/source/gui/GUI.h
+++ /dev/null
@@ -1,38 +0,0 @@
-/* Copyright (C) 2019 Wildfire Games.
- * This file is part of 0 A.D.
- *
- * 0 A.D. is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 2 of the License, or
- * (at your option) any later version.
- *
- * 0 A.D. is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef INCLUDED_GUI
-#define INCLUDED_GUI
-
-#include <map>
-#include <stddef.h>
-#include <string>
-#include <vector>
-
-#include "ps/CStr.h"
-
-#include "CGUIList.h"
-#include "CGUISeries.h"
-#include "CGUIText.h"
-#include "GUIbase.h"
-#include "IGUIButtonBehavior.h"
-#include "IGUIObject.h"
-#include "IGUIScrollBarOwner.h" // Required by IGUIScrollBar
-#include "IGUIScrollBar.h"
-#include "IGUITextOwner.h"
-
-#endif // INCLUDED_GUI
diff --git a/source/gui/GUIManager.h b/source/gui/GUIManager.h
index 9dacb601bf..2c37e2d280 100644
--- a/source/gui/GUIManager.h
+++ b/source/gui/GUIManager.h
@@ -28,6 +28,8 @@
 #include "scriptinterface/ScriptVal.h"
 #include "scriptinterface/ScriptInterface.h"
 
+#include <string>
+
 class CGUI;
 class JSObject;
 class IGUIObject;
@@ -175,7 +177,7 @@ private:
 	shared_ptr<ScriptRuntime> m_ScriptRuntime;
 	shared_ptr<ScriptInterface> m_ScriptInterface;
 
-	typedef std::vector<SGUIPage> PageStackType;
+	using PageStackType = std::vector<SGUIPage>;
 	PageStackType m_PageStack;
 
 	CTemplateLoader m_TemplateLoader;
diff --git a/source/gui/GUIRenderer.h b/source/gui/GUIRenderer.h
index 9c90ae1da1..93bffc7673 100644
--- a/source/gui/GUIRenderer.h
+++ b/source/gui/GUIRenderer.h
@@ -25,6 +25,7 @@
 #include "ps/CStr.h"
 #include "ps/Shapes.h"
 
+#include <map>
 #include <vector>
 
 class CGUISprite;
diff --git a/source/gui/GUITooltip.cpp b/source/gui/GUITooltip.cpp
index 5b4849ac67..b14f92178a 100644
--- a/source/gui/GUITooltip.cpp
+++ b/source/gui/GUITooltip.cpp
@@ -19,9 +19,8 @@
 
 #include "GUITooltip.h"
 
-#include "CGUI.h"
-#include "IGUIObject.h"
-
+#include "gui/CGUI.h"
+#include "gui/IGUIObject.h"
 #include "lib/timer.h"
 #include "ps/CLogger.h"
 
diff --git a/source/gui/GUIbase.cpp b/source/gui/GUIbase.cpp
index e358f63983..2f32631ef7 100644
--- a/source/gui/GUIbase.cpp
+++ b/source/gui/GUIbase.cpp
@@ -17,9 +17,9 @@
 
 #include "precompiled.h"
 
-#include "GUI.h"
-#include "gui/scripting/JSInterface_GUITypes.h"
+#include "GUIbase.h"
 
+#include "gui/scripting/JSInterface_GUITypes.h"
 #include "ps/CLogger.h"
 
 CClientArea::CClientArea() : pixel(0.f,0.f,0.f,0.f), percent(0.f,0.f,0.f,0.f)
diff --git a/source/gui/GUIbase.h b/source/gui/GUIbase.h
index 3d84431872..dcaad9ac9c 100644
--- a/source/gui/GUIbase.h
+++ b/source/gui/GUIbase.h
@@ -18,35 +18,24 @@
 /*
 GUI Core, stuff that the whole GUI uses
 
---Overview--
-
 	Contains defines, includes, types etc that the whole
 	 GUI should have included.
-
---More info--
-
-	Check GUI.h
-
 */
 
 #ifndef INCLUDED_GUIBASE
 #define INCLUDED_GUIBASE
 
-#include <map>
-#include <vector>
-
 #include "gui/CGUIColor.h"
 #include "ps/CStr.h"
 #include "ps/Errors.h"
-// I would like to just forward declare CSize, but it doesn't
-//  seem to be defined anywhere in the predefined header.
 #include "ps/Shapes.h"
 #include "scriptinterface/ScriptInterface.h"
 
+#include <map>
+#include <vector>
+
 class IGUIObject;
 
-// Object settings setups
-// Setup an object's ConstructObject function
 #define GUI_OBJECT(obj)													\
 public:																	\
 	static IGUIObject* ConstructObject(CGUI& pGUI)					\
@@ -130,8 +119,8 @@ enum EAlign { EAlign_Left, EAlign_Right, EAlign_Center };
 enum EVAlign { EVAlign_Top, EVAlign_Bottom, EVAlign_Center };
 
 // Typedefs
-typedef	std::map<CStr, IGUIObject*> map_pObjects;
-typedef std::vector<IGUIObject*> vector_pObjects;
+using map_pObjects = std::map<CStr, IGUIObject*>;
+using vector_pObjects = std::vector<IGUIObject*>;
 
 // Icon, you create them in the XML file with root element <setup>
 //  you use them in text owned by different objects... Such as CText.
diff --git a/source/gui/GUItypes.h b/source/gui/GUItypes.h
index 6c90f3af1e..4ce524b038 100644
--- a/source/gui/GUItypes.h
+++ b/source/gui/GUItypes.h
@@ -25,6 +25,9 @@ places, and to make it much easier to add a new type). Just do
 to handle every possible type.
 */
 
+#include "gui/CGUIList.h"
+#include "gui/CGUISeries.h"
+
 #ifndef GUITYPE_IGNORE_COPYABLE
 TYPE(bool)
 TYPE(i32)
diff --git a/source/gui/IGUIButtonBehavior.cpp b/source/gui/IGUIButtonBehavior.cpp
index cb75ff1877..d678f8b308 100644
--- a/source/gui/IGUIButtonBehavior.cpp
+++ b/source/gui/IGUIButtonBehavior.cpp
@@ -17,9 +17,9 @@
 
 #include "precompiled.h"
 
-#include "GUI.h"
-
 #include "gui/CGUI.h"
+#include "gui/CGUISprite.h"
+#include "gui/IGUIButtonBehavior.h"
 
 IGUIButtonBehavior::IGUIButtonBehavior(CGUI& pGUI)
 	: IGUIObject(pGUI), m_Pressed(false)
diff --git a/source/gui/IGUIButtonBehavior.h b/source/gui/IGUIButtonBehavior.h
index 8db3816c34..d3bf269dcc 100644
--- a/source/gui/IGUIButtonBehavior.h
+++ b/source/gui/IGUIButtonBehavior.h
@@ -16,26 +16,16 @@
  */
 
 /*
-GUI Object Base - Button Behavior
-
---Overview--
-
 	Interface class that enhance the IGUIObject with
 	 buttony behavior (click and release to click a button),
 	 and the GUI message GUIM_PRESSED.
 	When creating a class with extended settings and
 	 buttony behavior, just do a multiple inheritance.
-
---More info--
-
-	Check GUI.h
-
 */
 
 #ifndef INCLUDED_IGUIBUTTONBEHAVIOR
 #define INCLUDED_IGUIBUTTONBEHAVIOR
 
-#include "gui/GUI.h"
 #include "gui/IGUIObject.h"
 
 class CGUISpriteInstance;
@@ -44,8 +34,6 @@ class CGUISpriteInstance;
  * Appends button behaviours to the IGUIObject.
  * Can be used with multiple inheritance alongside
  * IGUISettingsObject and such.
- *
- * @see IGUIObject
  */
 class IGUIButtonBehavior : virtual public IGUIObject
 {
diff --git a/source/gui/IGUIObject.cpp b/source/gui/IGUIObject.cpp
index 6490924335..e232298802 100644
--- a/source/gui/IGUIObject.cpp
+++ b/source/gui/IGUIObject.cpp
@@ -17,8 +17,6 @@
 
 #include "precompiled.h"
 
-#include "GUI.h"
-
 #include "gui/CGUI.h"
 #include "gui/CGUISetting.h"
 #include "gui/scripting/JSInterface_GUITypes.h"
diff --git a/source/gui/IGUIObject.h b/source/gui/IGUIObject.h
index f3b535b9e0..d11ba3464c 100644
--- a/source/gui/IGUIObject.h
+++ b/source/gui/IGUIObject.h
@@ -30,6 +30,7 @@
 #include "lib/input.h" // just for IN_PASS
 #include "ps/XML/Xeromyces.h"
 
+#include <map>
 #include <string>
 #include <vector>
 
diff --git a/source/gui/IGUIScrollBar.cpp b/source/gui/IGUIScrollBar.cpp
index 9ea9fe5de6..d77ea75b3a 100644
--- a/source/gui/IGUIScrollBar.cpp
+++ b/source/gui/IGUIScrollBar.cpp
@@ -17,24 +17,25 @@
 
 #include "precompiled.h"
 
-#include "GUI.h"
+#include "IGUIScrollBar.h"
 
+#include "gui/IGUIScrollBarOwner.h"
 #include "gui/CGUI.h"
 #include "maths/MathUtil.h"
 
 IGUIScrollBar::IGUIScrollBar(CGUI& pGUI)
-								: m_pGUI(pGUI),
-								 m_pStyle(NULL),
-								 m_X(300.f), m_Y(300.f),
-								 m_ScrollRange(1.f), m_ScrollSpace(0.f), // MaxPos: not 0, due to division.
-								 m_Length(200.f), m_Width(20.f),
-								 m_BarSize(0.f), m_Pos(0.f),
-								 m_ButtonPlusPressed(false),
-								 m_ButtonMinusPressed(false),
-								 m_ButtonPlusHovered(false),
-								 m_ButtonMinusHovered(false),
-								 m_BarHovered(false),
-								 m_BarPressed(false)
+	: m_pGUI(pGUI),
+	 m_pStyle(nullptr),
+	 m_X(300.f), m_Y(300.f),
+	 m_ScrollRange(1.f), m_ScrollSpace(0.f), // MaxPos: not 0, due to division.
+	 m_Length(200.f), m_Width(20.f),
+	 m_BarSize(0.f), m_Pos(0.f),
+	 m_ButtonPlusPressed(false),
+	 m_ButtonMinusPressed(false),
+	 m_ButtonPlusHovered(false),
+	 m_ButtonMinusHovered(false),
+	 m_BarHovered(false),
+	 m_BarPressed(false)
 {
 }
 
diff --git a/source/gui/IGUIScrollBar.h b/source/gui/IGUIScrollBar.h
index ae294932e6..453bec5497 100644
--- a/source/gui/IGUIScrollBar.h
+++ b/source/gui/IGUIScrollBar.h
@@ -16,28 +16,17 @@
  */
 
 /*
-A GUI ScrollBar
-
---Overview--
-
 	A GUI Scrollbar, this class doesn't present all functionality
 	to the scrollbar, it just controls the drawing and a wrapper
 	for interaction with it.
-
---Usage--
-
-	Used in everywhere scrollbars are needed, like in a combobox for instance.
-
---More info--
-
-	Check GUI.h
-
 */
 
 #ifndef INCLUDED_IGUISCROLLBAR
 #define INCLUDED_IGUISCROLLBAR
 
-#include "GUI.h"
+#include "gui/CGUISprite.h"
+
+class IGUIScrollBarOwner;
 
 /**
  * The GUI Scroll-bar style. Tells us how scroll-bars look and feel.
@@ -386,12 +375,12 @@ protected:
 	/**
 	 * Pointer to scroll bar style used.
 	 */
-	SGUIScrollBarStyle *m_pStyle;
+	SGUIScrollBarStyle* m_pStyle;
 
 	/**
 	 * Host object, prerequisite!
 	 */
-	IGUIScrollBarOwner *m_pHostObject;
+	IGUIScrollBarOwner* m_pHostObject;
 
 	/**
 	 * Reference to CGUI object, these cannot work stand-alone
diff --git a/source/gui/IGUIScrollBarOwner.cpp b/source/gui/IGUIScrollBarOwner.cpp
index 7edf6a80d6..3a9b8d7b2e 100644
--- a/source/gui/IGUIScrollBarOwner.cpp
+++ b/source/gui/IGUIScrollBarOwner.cpp
@@ -17,8 +17,10 @@
 
 #include "precompiled.h"
 
-#include "GUI.h"
+#include "IGUIScrollBarOwner.h"
+
 #include "gui/CGUI.h"
+#include "gui/IGUIScrollBar.h"
 
 IGUIScrollBarOwner::IGUIScrollBarOwner(CGUI& pGUI)
 	: IGUIObject(pGUI)
diff --git a/source/gui/IGUIScrollBarOwner.h b/source/gui/IGUIScrollBarOwner.h
index e210fb0755..18d47f11f9 100644
--- a/source/gui/IGUIScrollBarOwner.h
+++ b/source/gui/IGUIScrollBarOwner.h
@@ -18,7 +18,9 @@
 #ifndef INCLUDED_IGUISCROLLBAROWNER
 #define INCLUDED_IGUISCROLLBAROWNER
 
-#include "GUI.h"
+#include "gui/IGUIObject.h"
+
+#include <vector>
 
 struct SGUIScrollBarStyle;
 class IGUIScrollBar;
@@ -26,9 +28,6 @@ class IGUIScrollBar;
 /**
  * Base-class this if you want an object to contain
  * one, or several, scroll-bars.
- *
- * @see IGUIObject
- * @see IGUIScrollBar
  */
 class IGUIScrollBarOwner : virtual public IGUIObject
 {
diff --git a/source/gui/IGUITextOwner.cpp b/source/gui/IGUITextOwner.cpp
index 6be5d71cbf..090b66240e 100644
--- a/source/gui/IGUITextOwner.cpp
+++ b/source/gui/IGUITextOwner.cpp
@@ -19,7 +19,6 @@
 
 #include "IGUITextOwner.h"
 
-#include "gui/GUI.h"
 #include "gui/CGUI.h"
 #include "gui/scripting/JSInterface_IGUITextOwner.h"
 
diff --git a/source/gui/IGUITextOwner.h b/source/gui/IGUITextOwner.h
index c41ffec38f..3a3f15a7ce 100644
--- a/source/gui/IGUITextOwner.h
+++ b/source/gui/IGUITextOwner.h
@@ -25,23 +25,19 @@ GUI Object Base - Text Owner
 	 and many controls that will use CGUIStrings might
 	 not use this, but does help for regular usage such
 	 as a text-box, a button, a radio button etc.
-
---More info--
-
-	Check GUI.h
-
 */
 
 #ifndef INCLUDED_IGUITEXTOWNER
 #define INCLUDED_IGUITEXTOWNER
 
-#include "GUI.h"
+#include "gui/CGUIText.h"
+#include "gui/IGUIObject.h"
 #include "gui/scripting/JSInterface_IGUITextOwner.h"
 
+#include <vector>
+
 /**
  * Framework for handling Output text.
- *
- * @see IGUIObject
  */
 class IGUITextOwner : virtual public IGUIObject
 {
diff --git a/source/gui/MiniMap.cpp b/source/gui/MiniMap.cpp
index 0dc81ee976..f6a9955917 100644
--- a/source/gui/MiniMap.cpp
+++ b/source/gui/MiniMap.cpp
@@ -29,7 +29,6 @@
 #include "graphics/TerrainTextureManager.h"
 #include "graphics/TerritoryTexture.h"
 #include "gui/CGUI.h"
-#include "gui/GUI.h"
 #include "gui/GUIManager.h"
 #include "gui/GUIMatrix.h"
 #include "lib/bits.h"
diff --git a/source/gui/MiniMap.h b/source/gui/MiniMap.h
index 4f2474a695..b8f6f35bbd 100644
--- a/source/gui/MiniMap.h
+++ b/source/gui/MiniMap.h
@@ -18,7 +18,8 @@
 #ifndef INCLUDED_MINIMAP
 #define INCLUDED_MINIMAP
 
-#include "gui/GUI.h"
+#include "gui/IGUIObject.h"
+#include "graphics/ShaderProgramPtr.h"
 #include "renderer/VertexArray.h"
 
 class CCamera;
diff --git a/source/gui/scripting/GuiScriptConversions.cpp b/source/gui/scripting/GuiScriptConversions.cpp
index 068780280c..f0ae9e59e4 100644
--- a/source/gui/scripting/GuiScriptConversions.cpp
+++ b/source/gui/scripting/GuiScriptConversions.cpp
@@ -27,6 +27,8 @@
 #include "ps/Hotkey.h"
 #include "scriptinterface/ScriptConversions.h"
 
+#include <string>
+
 #define SET(obj, name, value) STMT(JS::RootedValue v_(cx); AssignOrToJSVal(cx, &v_, (value)); JS_SetProperty(cx, obj, (name), v_))
 	// ignore JS_SetProperty return value, because errors should be impossible
 	// and we can't do anything useful in the case of errors anyway
diff --git a/source/pch/gui/precompiled.h b/source/pch/gui/precompiled.h
index 07c06ca4d2..61ff4379e8 100644
--- a/source/pch/gui/precompiled.h
+++ b/source/pch/gui/precompiled.h
@@ -24,8 +24,9 @@
 
 #if HAVE_PCH
 
+#include "gui/CGUI.h"
+#include "gui/IGUIObject.h"
 #include "ps/CStr.h"
-#include "gui/GUI.h"
 #include "scriptinterface/ScriptInterface.h"
 
 #endif // HAVE_PCH
diff --git a/source/ps/GameSetup/GameSetup.cpp b/source/ps/GameSetup/GameSetup.cpp
index 418b691cce..d4e3051ce5 100644
--- a/source/ps/GameSetup/GameSetup.cpp
+++ b/source/ps/GameSetup/GameSetup.cpp
@@ -36,7 +36,6 @@
 #include "graphics/MaterialManager.h"
 #include "graphics/TerrainTextureManager.h"
 #include "gui/CGUI.h"
-#include "gui/GUI.h"
 #include "gui/GUIManager.h"
 #include "i18n/L10n.h"
 #include "maths/MathUtil.h"
diff --git a/source/tools/atlas/GameInterface/Handlers/MiscHandlers.cpp b/source/tools/atlas/GameInterface/Handlers/MiscHandlers.cpp
index ecfe8e67a5..c2684f6878 100644
--- a/source/tools/atlas/GameInterface/Handlers/MiscHandlers.cpp
+++ b/source/tools/atlas/GameInterface/Handlers/MiscHandlers.cpp
@@ -25,9 +25,9 @@
 #include "graphics/CinemaManager.h"
 #include "graphics/GameView.h"
 #include "gui/GUIManager.h"
-#include "gui/GUI.h"
 #include "gui/CGUI.h"
 #include "lib/external_libraries/libsdl.h"
+#include "lib/ogl.h"
 #include "lib/sysdep/cpu.h"
 #include "maths/MathUtil.h"
 #include "ps/Game.h"