--- a/src/gfx.cpp	Mon Apr 07 20:18:51 2008 +0000
+++ b/src/gfx.cpp	Mon Apr 07 20:28:58 2008 +0000
@@ -28,10 +28,10 @@
 bool _ctrl_pressed;   ///< Is Ctrl pressed?
 bool _shift_pressed;  ///< Is Shift pressed?
 byte _fast_forward;
-bool _left_button_down;
-bool _left_button_clicked;
-bool _right_button_down;
-bool _right_button_clicked;
+bool _left_button_down;     ///< Is left mouse button pressed?
+bool _left_button_clicked;  ///< Is left mouse button clicked?
+bool _right_button_down;    ///< Is right mouse button pressed?
+bool _right_button_clicked; ///< Is right mouse button clicked?
 DrawPixelInfo _screen;
 bool _screen_disable_anim = false;   ///< Disable palette animation (important for 32bpp-anim blitter during giant screenshot)
 bool _exit_game;

--- a/src/main_gui.cpp	Mon Apr 07 20:18:51 2008 +0000
+++ b/src/main_gui.cpp	Mon Apr 07 20:28:58 2008 +0000
@@ -1214,6 +1214,10 @@
 	WP(w, def_d).data_1 = -1280;
 }
 
+/**
+ * Size of the application screen changed.
+ * Adapt the game screen-size, re-allocate the open windows, and repaint everything
+ */
 void GameSizeChanged()
 {
 	_cur_resolution[0] = _screen.width;

--- a/src/sound.cpp	Mon Apr 07 20:18:51 2008 +0000
+++ b/src/sound.cpp	Mon Apr 07 20:28:58 2008 +0000
@@ -197,9 +197,7 @@
 
 void SndCopyToPool()
 {
-	uint i;
-
-	for (i = 0; i < _file_count; i++) {
+	for (uint i = 0; i < _file_count; i++) {
 		FileEntry *orig = &_files[_sound_idx[i]];
 		FileEntry *fe = AllocateFileEntry();
 

--- a/src/station_gui.cpp	Mon Apr 07 20:18:51 2008 +0000
+++ b/src/station_gui.cpp	Mon Apr 07 20:28:58 2008 +0000
@@ -388,7 +388,7 @@
 
 				assert(st->xy != 0);
 
- 				/* Do not do the complex check HasStationInUse here, it may be even false
+				/* Do not do the complex check HasStationInUse here, it may be even false
 				 * when the order had been removed and the station list hasn't been removed yet */
 				assert(st->owner == owner || (st->owner == OWNER_NONE && !st->IsBuoy()));
 

--- a/src/viewport_type.h	Mon Apr 07 20:18:51 2008 +0000
+++ b/src/viewport_type.h	Mon Apr 07 20:28:58 2008 +0000
@@ -10,12 +10,19 @@
 #include "window_type.h"
 #include "tile_type.h"
 
+/**
+ * Data structure for viewport, display of a part of the world
+ */
 struct ViewPort {
-	int left,top;                       // screen coordinates for the viewport
-	int width, height;                  // screen width/height for the viewport
+	int left;    ///< Screen coordinate left egde of the viewport
+	int top;     ///< Screen coordinate top edge of the viewport
+	int width;   ///< Screen width of the viewport
+	int height;  ///< Screen height of the viewport
 
-	int virtual_left, virtual_top;      // virtual coordinates
-	int virtual_width, virtual_height;  // these are just width << zoom, height << zoom
+	int virtual_left;    ///< Virtual left coordinate
+	int virtual_top;     ///< Virtual top coordinate
+	int virtual_width;   ///< width << zoom
+	int virtual_height;  ///< height << zoom
 
 	ZoomLevel zoom;
 };
@@ -58,7 +65,7 @@
 	VHM_RAIL    = 5, ///< rail pieces
 };
 
-/* highlighting draw styles */
+/** Highlighting draw styles */
 enum HighLightStyle {
 	HT_NONE   = 0x00,
 	HT_RECT   = 0x80,

--- a/src/widget.cpp	Mon Apr 07 20:18:51 2008 +0000
+++ b/src/widget.cpp	Mon Apr 07 20:28:58 2008 +0000
@@ -186,6 +186,10 @@
 }
 
 
+/**
+ * Paint all widgets of a window.
+ * @param w Window
+ */
 void DrawWindowWidgets(const Window *w)
 {
 	const DrawPixelInfo* dpi = _cur_dpi;
@@ -569,6 +573,7 @@
 	}
 }
 
+/** Resize a widget and shuffle other widgets around to fit. */
 void ResizeWindowForWidget(Window *w, int widget, int delta_x, int delta_y)
 {
 	int right  = w->widget[widget].right;

--- a/src/widgets/dropdown.cpp	Mon Apr 07 20:18:51 2008 +0000
+++ b/src/widgets/dropdown.cpp	Mon Apr 07 20:28:58 2008 +0000
@@ -313,6 +313,10 @@
 	ShowDropDownList(w, list, selected, button);
 }
 
+/**
+ * Delete the drop-down menu from window \a pw
+ * @param pw Parent window of the drop-down menu window
+ */
 void HideDropDownMenu(Window *pw)
 {
 	Window **wz;

--- a/src/window.cpp	Mon Apr 07 20:18:51 2008 +0000
+++ b/src/window.cpp	Mon Apr 07 20:28:58 2008 +0000
@@ -22,10 +22,16 @@
 
 #include "table/sprites.h"
 
-/* delta between mouse cursor and upper left corner of dragged window */
+/** delta between mouse cursor and upper left corner of dragged window */
 static Point _drag_delta;
 
 static Window _windows[MAX_NUMBER_OF_WINDOWS];
+
+/**
+ * List of windows opened at the screen.
+ * Uppermost window is at  _z_windows[_last_z_window - 1],
+ * bottom window is at _z_windows[0]
+ */
 Window *_z_windows[lengthof(_windows)];
 Window **_last_z_window; ///< always points to the next free space in the z-array
 
@@ -116,6 +122,13 @@
 static void StartWindowDrag(Window *w);
 static void StartWindowSizing(Window *w);
 
+/**
+ * Dispatch left mouse-button (possibly double) click in window.
+ * @param w Window to dispatch event in
+ * @param x X coordinate of the click
+ * @param y Y coordinate of the click
+ * @param double_click Was it a double click?
+ */
 static void DispatchLeftClickEvent(Window *w, int x, int y, bool double_click)
 {
 	WindowEvent e;
@@ -175,6 +188,12 @@
 	w->wndproc(w, &e);
 }
 
+/**
+ * Dispatch right mouse-button click in window.
+ * @param w Window to dispatch event in
+ * @param x X coordinate of the click
+ * @param y Y coordinate of the click
+ */
 static void DispatchRightClickEvent(Window *w, int x, int y)
 {
 	WindowEvent e;
@@ -197,9 +216,10 @@
 	w->wndproc(w, &e);
 }
 
-/** Dispatch the mousewheel-action to the window which will scroll any
- * compatible scrollbars if the mouse is pointed over the bar or its contents
- * @param *w Window
+/**
+ * Dispatch the mousewheel-action to the window.
+ * The window will scroll any compatible scrollbars if the mouse is pointed over the bar or its contents
+ * @param w Window
  * @param widget the widget where the scrollwheel was used
  * @param wheel scroll up or down
  */
@@ -232,6 +252,14 @@
 
 static void DrawOverlappedWindow(Window* const *wz, int left, int top, int right, int bottom);
 
+/**
+ * From a rectangle that needs redrawing, find the windows that intersect with the rectangle.
+ * These windows should be re-painted.
+ * @param left Left edge of the rectangle that should be repainted
+ * @param top Top edge of the rectangle that should be repainted
+ * @param right Right edge of the rectangle that should be repainted
+ * @param bottom Bottom edge of the rectangle that should be repainted
+ */
 void DrawOverlappedWindowForAll(int left, int top, int right, int bottom)
 {
 	Window* const *wz;
@@ -249,10 +277,23 @@
 	}
 }
 
+/**
+ * Generate repaint events for the visible part of window *wz within the rectangle.
+ *
+ * The function goes recursively upwards in the window stack, and splits the rectangle
+ * into multiple pieces at the window edges, so obscured parts are not redrawn.
+ *
+ * @param wz Pointer into window stack, pointing at the window that needs to be repainted
+ * @param left Left edge of the rectangle that should be repainted
+ * @param top Top edge of the rectangle that should be repainted
+ * @param right Right edge of the rectangle that should be repainted
+ * @param bottom Bottom edge of the rectangle that should be repainted
+ *
+ * @todo Swap this function to above DrawOverlappedWindowForAll() to eliminate the forward declaration
+ */
 static void DrawOverlappedWindow(Window* const *wz, int left, int top, int right, int bottom)
 {
 	Window* const *vz = wz;
-	int x;
 
 	while (++vz != _last_z_window) {
 		const Window *v = *vz;
@@ -261,6 +302,9 @@
 				bottom > v->top &&
 				left < v->left + v->width &&
 				top < v->top + v->height) {
+			/* v and rectangle intersect with eeach other */
+			int x;
+
 			if (left < (x = v->left)) {
 				DrawOverlappedWindow(wz, left, top, x, bottom);
 				DrawOverlappedWindow(wz, x, top, right, bottom);
@@ -302,6 +346,12 @@
 	}
 }
 
+/**
+ * Dispatch an event to a possibly non-existing window.
+ * If the window pointer w is \c NULL, the event is not dispatched
+ * @param w Window to dispatch the event to, may be \c NULL
+ * @param event Event to dispatch
+ */
 void CallWindowEventNP(Window *w, int event)
 {
 	WindowEvent e;
@@ -310,6 +360,11 @@
 	w->wndproc(w, &e);
 }
 
+/**
+ * Mark entire window as dirty (in need of re-paint)
+ * @param w Window to redraw
+ * @ingroup dirty
+ */
 void SetWindowDirty(const Window *w)
 {
 	if (w == NULL) return;
@@ -334,12 +389,13 @@
 /** Find the z-value of a window. A window must already be open
  * or the behaviour is undefined but function should never fail
  * @param w window to query Z Position
- * @return the window that matches it */
+ * @return Pointer into the window-list at the position of \a w
+ */
 Window **FindWindowZPosition(const Window *w)
 {
 	Window **wz;
 
-	for (wz = _z_windows; wz != _last_z_window; wz++) {
+	FOR_ALL_WINDOWS(wz) {
 		if (*wz == w) return wz;
 	}
 
@@ -348,14 +404,15 @@
 	return NULL;
 }
 
+/**
+ * Remove window and all its child windows from the window stack
+ */
 void DeleteWindow(Window *w)
 {
-	Window *v;
-	Window **wz;
 	if (w == NULL) return;
 
 	/* Delete any children a window might have in a head-recursive manner */
-	v = FindChildWindow(w);
+	Window *v = FindChildWindow(w);
 	if (v != NULL) DeleteWindow(v);
 
 	if (_thd.place_mode != VHM_NONE &&
@@ -375,12 +432,18 @@
 
 	/* Find the window in the z-array, and effectively remove it
 	 * by moving all windows after it one to the left */
-	wz = FindWindowZPosition(w);
+	Window **wz = FindWindowZPosition(w);
 	if (wz == NULL) return;
 	memmove(wz, wz + 1, (byte*)_last_z_window - (byte*)wz);
 	_last_z_window--;
 }
 
+/**
+ * Find a window by its class and window number
+ * @param cls Window class
+ * @param number Number of the window within the window class
+ * @return Pointer to the found window, or \c NULL if not available
+ */
 Window *FindWindowById(WindowClass cls, WindowNumber number)
 {
 	Window* const *wz;
@@ -393,11 +456,20 @@
 	return NULL;
 }
 
+/**
+ * Delete a window by its class and window number (if it is open).
+ * @param cls Window class
+ * @param number Number of the window within the window class
+ */
 void DeleteWindowById(WindowClass cls, WindowNumber number)
 {
 	DeleteWindow(FindWindowById(cls, number));
 }
 
+/**
+ * Delete all windows of a given class
+ * @param cls Window class of windows to delete
+ */
 void DeleteWindowByClass(WindowClass cls)
 {
 	Window* const *wz;
@@ -625,9 +697,8 @@
  * @param window_number number being assigned to the new window
  * @param data the data to be given during the WE_CREATE message
  * @return Window pointer of the newly created window */
-static Window *LocalAllocateWindow(
-							int x, int y, int min_width, int min_height, int def_width, int def_height,
-							WindowProc *proc, WindowClass cls, const Widget *widget, int window_number, void *data)
+static Window *LocalAllocateWindow(int x, int y, int min_width, int min_height, int def_width, int def_height,
+				WindowProc *proc, WindowClass cls, const Widget *widget, int window_number, void *data)
 {
 	Window *w = FindFreeWindow();
 
@@ -751,18 +822,14 @@
  * @param *proc see WindowProc function to call when any messages/updates happen to the window
  * @param cls see WindowClass class of the window, used for identification and grouping
  * @param *widget see Widget pointer to the window layout and various elements
- * @return Window pointer of the newly created window */
-Window *AllocateWindow(
-							int x, int y, int width, int height,
-							WindowProc *proc, WindowClass cls, const Widget *widget, void *data)
+ * @return Window pointer of the newly created window
+ */
+Window *AllocateWindow(int x, int y, int width, int height,
+			WindowProc *proc, WindowClass cls, const Widget *widget, void *data)
 {
 	return LocalAllocateWindow(x, y, width, height, width, height, proc, cls, widget, 0, data);
 }
 
-struct SizeRect {
-	int left,top,width,height;
-};
-
 
 static bool IsGoodAutoPlace1(int left, int top, int width, int height, Point &pos)
 {
@@ -1002,7 +1069,7 @@
 
 restart_search:
 	/* Delete all windows, reset z-array.
-	 *When we find the window to delete, we need to restart the search
+	 * When we find the window to delete, we need to restart the search
 	 * as deleting this window could cascade in deleting (many) others
 	 * anywhere in the z-array. We call DeleteWindow() so that it can properly
 	 * release own alloc'd memory, which otherwise could result in memleaks */
@@ -1158,12 +1225,15 @@
 	return true;
 }
 
-/** Update all the widgets of a window based on their resize flags
+/**
+ * Resize the window.
+ * Update all the widgets of a window based on their resize flags
  * Both the areas of the old window and the new sized window are set dirty
  * ensuring proper redrawal.
  * @param w Window to resize
  * @param x delta x-size of changed window (positive if larger, etc.)
- * @param y delta y-size of changed window */
+ * @param y delta y-size of changed window
+ */
 void ResizeWindow(Window *w, int x, int y)
 {
 	Widget *wi;
@@ -1409,6 +1479,10 @@
 	return false;
 }
 
+/**
+ * Start window dragging
+ * @param w Window to start dragging
+ */
 static void StartWindowDrag(Window *w)
 {
 	w->flags4 |= WF_DRAGGING;
@@ -1421,6 +1495,10 @@
 	DeleteWindowById(WC_DROPDOWN_MENU, 0);
 }
 
+/**
+ * Start resizing a window
+ * @param w Window to start resizing
+ */
 static void StartWindowSizing(Window *w)
 {
 	w->flags4 |= WF_SIZING;
@@ -1632,11 +1710,10 @@
 }
 
 /** Handle keyboard input.
- * @param key Lower 8 bits contain the ASCII character, the higher
- * 16 bits the keycode */
+ * @param key Lower 8 bits contain the ASCII character, the higher 16 bits the keycode
+ */
 void HandleKeypress(uint32 key)
 {
-	Window* const *wz;
 	WindowEvent e;
 	/* Stores if a window with a textfield for typing is open
 	 * If this is the case, keypress events are only passed to windows with text fields and
@@ -1685,7 +1762,7 @@
 	}
 
 	/* Call the event, start with the uppermost window. */
-	for (wz = _last_z_window; wz != _z_windows;) {
+	for (Window* const *wz = _last_z_window; wz != _z_windows;) {
 		Window *w = *--wz;
 
 		/* if a query window is open, only call the event for certain window types */
@@ -1709,6 +1786,9 @@
 	}
 }
 
+/**
+ * State of CONTROL key has changed
+ */
 void HandleCtrlChanged()
 {
 	WindowEvent e;
@@ -1727,8 +1807,18 @@
 extern void UpdateTileSelection();
 extern bool VpHandlePlaceSizingDrag();
 
+/**
+ * Local counter that is incremented each time an mouse input event is detected.
+ * The counter is used to stop auto-scrolling.
+ * @see HandleAutoscroll()
+ * @see HandleMouseEvents()
+ */
 static int _input_events_this_tick = 0;
 
+/**
+ * If needed and switched on, perform auto scrolling (automatically
+ * moving window contents when mouse is near edge of the window).
+ */
 static void HandleAutoscroll()
 {
 	Window *w;
@@ -1870,6 +1960,9 @@
 	}
 }
 
+/**
+ * Handle a mouse event from the video driver
+ */
 void HandleMouseEvents()
 {
 	static int double_click_time = 0;
@@ -1919,12 +2012,18 @@
 	MouseLoop(click, mousewheel);
 }
 
+/**
+ * Regular call from the global game loop
+ */
 void InputLoop()
 {
 	HandleMouseEvents();
 	HandleAutoscroll();
 }
 
+/**
+ * Update the continuously changing contents of the windows, such as the viewports
+ */
 void UpdateWindows()
 {
 	Window* const *wz;
@@ -1959,6 +2058,13 @@
 }
 
 
+/**
+ * In a window with menu_d custom extension, retrieve the menu item number from a position
+ * @param w Window holding the menu items
+ * @param x X coordinate of the position
+ * @param y Y coordinate of the position
+ * @return Index number of the menu item, or \c -1 if no valid selection under position
+ */
 int GetMenuItemIndex(const Window *w, int x, int y)
 {
 	if ((x -= w->left) >= 0 && x < w->width && (y -= w->top + 1) >= 0) {
@@ -1972,6 +2078,10 @@
 	return -1;
 }
 
+/**
+ * Mark window data as invalid (in need of re-computing)
+ * @param w Window with invalid data
+ */
 void InvalidateWindow(WindowClass cls, WindowNumber number)
 {
 	Window* const *wz;
@@ -1982,6 +2092,12 @@
 	}
 }
 
+/*
+ * Mark a particular widget in a particular window as dirty (in need of repainting)
+ * @param cls Window class
+ * @param number Window number in that class
+ * @param widget_index Index number of the widget that needs repainting
+ */
 void InvalidateWindowWidget(WindowClass cls, WindowNumber number, byte widget_index)
 {
 	Window* const *wz;
@@ -1994,6 +2110,10 @@
 	}
 }
 
+/*
+ * Mark all windows of a particular class as dirty (in need of repainting)
+ * @param cls Window class
+ */
 void InvalidateWindowClasses(WindowClass cls)
 {
 	Window* const *wz;
@@ -2003,12 +2123,21 @@
 	}
 }
 
+/**
+ * Mark window data as invalid (in need of re-computing)
+ * @param w Window with invalid data
+ */
 void InvalidateThisWindowData(Window *w)
 {
 	CallWindowEventNP(w, WE_INVALIDATE_DATA);
 	SetWindowDirty(w);
 }
 
+/**
+ * Mark window data the window of a given class and specific window number as invalid (in need of re-computing)
+ * @param cls Window class
+ * @param number Window number within the class
+ */
 void InvalidateWindowData(WindowClass cls, WindowNumber number)
 {
 	Window* const *wz;
@@ -2019,6 +2148,10 @@
 	}
 }
 
+/**
+ * Mark window data of all windows of a given class as invalid (in need of re-computing)
+ * @param cls Window class
+ */
 void InvalidateWindowClassesData(WindowClass cls)
 {
 	Window* const *wz;
@@ -2028,6 +2161,9 @@
 	}
 }
 
+/**
+ * Dispatch WE_TICK event over all windows
+ */
 void CallWindowTickEvent()
 {
 	Window* const *wz;
@@ -2093,6 +2229,11 @@
 	DeleteWindowById(WC_STATUS_BAR, 0);
 }
 
+/**
+ * (Re)position main toolbar window at the screen
+ * @param w Window structure of the main toolbar window, may also be \c NULL
+ * @return X coordinate of left edge of the repositioned toolbar window
+ */
 int PositionMainToolbar(Window *w)
 {
 	DEBUG(misc, 5, "Repositioning Main Toolbar...");
@@ -2110,6 +2251,11 @@
 	return w->left;
 }
 
+/**
+ * Relocate all windows to fit the new size of the game application screen
+ * @param neww New width of the game application screen
+ * @param newh New height of the game appliction screen
+ */
 void RelocateAllWindows(int neww, int newh)
 {
 	Window* const *wz;

--- a/src/window_func.h	Mon Apr 07 20:18:51 2008 +0000
+++ b/src/window_func.h	Mon Apr 07 20:28:58 2008 +0000
@@ -8,11 +8,6 @@
 #include "window_type.h"
 #include "player_type.h"
 
-/**
- * Marks the window as dirty for repaint.
- *
- * @ingroup dirty
- */
 void SetWindowDirty(const Window *w);
 void SendWindowMessage(WindowClass wnd_class, WindowNumber wnd_num, int msg, int wparam, int lparam);
 void SendWindowMessageClass(WindowClass wnd_class, int msg, int wparam, int lparam);

--- a/src/window_gui.h	Mon Apr 07 20:18:51 2008 +0000
+++ b/src/window_gui.h	Mon Apr 07 20:28:58 2008 +0000
@@ -73,6 +73,9 @@
 	WIDGET_LIST_END = -1, ///< indicate the end of widgets' list for vararg functions
 };
 
+/**
+ * Window widget data structure
+ */
 struct Widget {
 	byte type;                        ///< Widget type, see WindowWidgetTypes
 	byte display_flags;               ///< Resize direction, alignment, etc. during resizing, see ResizeFlags
@@ -82,6 +85,9 @@
 	StringID tooltips;                ///< Tooltips that are shown when rightclicking on a widget
 };
 
+/**
+ * Flags to describe the look of the frame
+ */
 enum FrameFlags {
 	FR_NONE         =  0,
 	FR_TRANSPARENT  =  1 << 0,  ///< Makes the background transparent if set
@@ -92,21 +98,25 @@
 
 DECLARE_ENUM_AS_BIT_SET(FrameFlags);
 
+/* wiget.cpp */
 void DrawFrameRect(int left, int top, int right, int bottom, int color, FrameFlags flags);
 
+/**
+ * Available window events
+ */
 enum WindowEventCodes {
-	WE_CREATE,
-	WE_DESTROY,
-	WE_PAINT,
-	WE_KEYPRESS,
-	WE_CLICK,
-	WE_DOUBLE_CLICK,
-	WE_RCLICK,
+	WE_CREATE,       ///< Initialize the Window
+	WE_DESTROY,      ///< Prepare for deletion of the window
+	WE_PAINT,        ///< Repaint the window contents
+	WE_KEYPRESS,     ///< Key pressed
+	WE_CLICK,        ///< Left mouse button click
+	WE_DOUBLE_CLICK, ///< Left mouse button double click
+	WE_RCLICK,       ///< Right mouse button click
 	WE_MOUSEOVER,
 	WE_MOUSELOOP,
 	WE_MOUSEWHEEL,
-	WE_TICK,
-	WE_4,
+	WE_TICK,         ///< Regularly occurring event (about once every 20 seconds orso, 10 days) for slowly changing content (typically list sorting)
+	WE_4,            ///< Regularly occurring event for updating continuously changing window content (other than view ports), or timer expiring
 	WE_TIMEOUT,
 	WE_PLACE_OBJ,
 	WE_ABORT_PLACE_OBJ,
@@ -119,13 +129,17 @@
 	WE_PLACE_MOUSEUP,
 	WE_PLACE_PRESIZE,
 	WE_DROPDOWN_SELECT,
-	WE_RESIZE,
-	WE_MESSAGE,
+	WE_RESIZE,          ///< Request to resize the window, @see WindowEvent.we.resize
+	WE_MESSAGE,         ///< Receipt of a message from another window. @see WindowEvent.we.message, SendWindowMessage(), SendWindowMessageClass()
 	WE_SCROLL,
-	WE_INVALIDATE_DATA,
-	WE_CTRL_CHANGED,
+	WE_INVALIDATE_DATA, ///< Notification that data displayed by the window is obsolete
+	WE_CTRL_CHANGED,    ///< CTRL key has changed state
 };
 
+/**
+ * Data structures for additional data associated with a window event
+ * @see WindowEventCodes
+ */
 struct WindowEvent {
 	byte event;
 	union {
@@ -200,27 +214,40 @@
 	} we;
 };
 
+/**
+ * High level window description
+ */
 struct WindowDesc {
-	int16 left, top, minimum_width, minimum_height, default_width, default_height;
-	WindowClass cls;
-	WindowClass parent_cls;
-	uint32 flags;
-	const Widget *widgets;
-	WindowProc *proc;
+	int16 left;             ///< Prefered x position of left edge of the window, @see WindowDefaultPosition()
+	int16 top;              ///< Prefered y position of the top of the window, @see WindowDefaultPosition()
+	int16 minimum_width;    ///< Minimal width of the window
+	int16 minimum_height;   ///< Minimal height of the window
+	int16 default_width;    ///< Prefered initial width of the window
+	int16 default_height;   ///< Prefered initial height of the window
+	WindowClass cls;        ///< Class of the window, @see WindowClass
+	WindowClass parent_cls; ///< Class of the parent window, @see WindowClass
+	uint32 flags;           ///< Flags, @see WindowDefaultFlags
+	const Widget *widgets;  ///< List of widgets with their position and size for the window
+	WindowProc *proc;       ///< Window event handler function for the window
 };
 
+/**
+ * Window default widget/window handling flags
+ */
 enum WindowDefaultFlag {
 	WDF_STD_TOOLTIPS    =   1 << 0, ///< use standard routine when displaying tooltips
-	WDF_DEF_WIDGET      =   1 << 1, ///< default widget control for some widgets in the on click event
-	WDF_STD_BTN         =   1 << 2, ///< default handling for close and drag widgets (widget no 0 and 1)
+	WDF_DEF_WIDGET      =   1 << 1, ///< Default widget control for some widgets in the on click event, @see DispatchLeftClickEvent()
+	WDF_STD_BTN         =   1 << 2, ///< Default handling for close and titlebar widgets (widget no 0 and 1)
 
-	WDF_UNCLICK_BUTTONS =   1 << 4, ///< Unclick buttons when the window event times out */
+	WDF_UNCLICK_BUTTONS =   1 << 4, ///< Unclick buttons when the window event times out
 	WDF_STICKY_BUTTON   =   1 << 5, ///< Set window to sticky mode; they are not closed unless closed with 'X' (widget 2)
-	WDF_RESIZABLE       =   1 << 6, ///< A window can be resized
+	WDF_RESIZABLE       =   1 << 6, ///< Window can be resized
 	WDF_MODAL           =   1 << 7, ///< The window is a modal child of some other window, meaning the parent is 'inactive'
 };
 
-/* can be used as x or y coordinates to cause a specific placement */
+/**
+ * Special values for 'left' and 'top' to cause a specific placement
+ */
 enum WindowDefaultPosition {
 	WDP_AUTO      = -1, ///< Find a place automatically
 	WDP_CENTER    = -2, ///< Center the window (left/right or top/bottom)
@@ -230,46 +257,65 @@
 
 #define WP(ptr, str) (*(str*)(ptr)->custom)
 
+/**
+ * Scrollbar data structure
+ */
 struct Scrollbar {
-	uint16 count, cap, pos;
+	uint16 count;  ///< Number of elements in the list
+	uint16 cap;    ///< Number of visible elements of the scroll bar
+	uint16 pos;
 };
 
+/**
+ * Data structure for resizing a window
+ */
 struct ResizeInfo {
-	uint width; ///< Minimum width and height
-	uint height;
-	uint step_width; ///< In how big steps the width and height go
-	uint step_height;
+	uint width;       ///< Minimum allowed width of the window
+	uint height;      ///< Minimum allowed height of the window
+	uint step_width;  ///< Step-size of width resize changes
+	uint step_height; ///< Step-size of height resize changes
 };
 
+/**
+ * Message data structure for messages sent between winodows
+ * @see SendWindowMessageW()
+ */
 struct WindowMessage {
 	int msg;
 	int wparam;
 	int lparam;
 };
 
+/**
+ * Data structure for an opened window
+ */
 struct Window {
-	uint16 flags4;
-	WindowClass window_class;
-	WindowNumber window_number;
-
-	int left, top;
-	int width, height;
-
-	Scrollbar hscroll, vscroll, vscroll2;
-	ResizeInfo resize;
+	uint16 flags4;              ///< Window flags, @see WindowFlags
+	WindowClass window_class;   ///< Window class
+	WindowNumber window_number; ///< Window number within the window class
 
-	byte caption_color;
+	int left;   ///< x position of left edge of the window
+	int top;    ///< y position of top edge of the window
+	int width;  ///< width of the window (number of pixels to the right in x direction)
+	int height; ///< Height of the window (number of pixels down in y direction)
 
-	WindowProc *wndproc;
-	ViewPort *viewport;
-	const Widget *original_widget;
-	Widget *widget;
-	uint widget_count;
-	uint32 desc_flags;
+	Scrollbar hscroll;  ///< Horizontal scroll bar
+	Scrollbar vscroll;  ///< First vertical scroll bar
+	Scrollbar vscroll2; ///< Second vertical scroll bar
+	ResizeInfo resize;  ///< Resize information
 
-	WindowMessage message;
-	Window *parent;
-	byte custom[WINDOW_CUSTOM_SIZE];
+	byte caption_color; ///< Background color of the window caption, contains PlayerID
+
+	WindowProc *wndproc;   ///< Event handler function for the window
+	ViewPort *viewport;    ///< Pointer to viewport, if present (structure is part of derived class)
+	const Widget *original_widget; ///< Original widget layout, copied from WindowDesc
+	Widget *widget;        ///< Widgets of the window
+	uint widget_count;     ///< Number of widgets of the window
+	uint32 desc_flags;     ///< Window/widgets default flags setting, @see WindowDefaultFlag
+
+	WindowMessage message; ///< Buffer for storing received messages (for communication between different window events)
+	Window *parent;        ///< Parent window
+	byte custom[WINDOW_CUSTOM_SIZE]; ///< Additional data depending on window type
 
 	void HandleButtonClick(byte widget);
 
@@ -429,28 +475,31 @@
 };
 
 
+/**
+ * Window widget types
+ */
 enum WindowWidgetTypes {
-	WWT_EMPTY,
-
-	WWT_PANEL,      ///< simple depressed panel
-	WWT_INSET,      ///< pressed (inset) panel, most commonly used as combo box _text_ area
-	WWT_IMGBTN,     ///< button with image
-	WWT_IMGBTN_2,   ///< button with diff image when clicked
+	WWT_EMPTY,      ///< Empty widget, place holder to reserve space in widget array
 
-	WWT_TEXTBTN,    ///< button with text
-	WWT_TEXTBTN_2,  ///< button with diff text when clicked
-	WWT_LABEL,      ///< centered label
-	WWT_TEXT,       ///< pure simple text
-	WWT_MATRIX,
-	WWT_SCROLLBAR,
-	WWT_FRAME,      ///< frame
-	WWT_CAPTION,
+	WWT_PANEL,      ///< Simple depressed panel
+	WWT_INSET,      ///< Pressed (inset) panel, most commonly used as combo box _text_ area
+	WWT_IMGBTN,     ///< Button with image
+	WWT_IMGBTN_2,   ///< Button with diff image when clicked
 
-	WWT_HSCROLLBAR,
-	WWT_STICKYBOX,
+	WWT_TEXTBTN,    ///< Button with text
+	WWT_TEXTBTN_2,  ///< Button with diff text when clicked
+	WWT_LABEL,      ///< Centered label
+	WWT_TEXT,       ///< Pure simple text
+	WWT_MATRIX,     ///< List of items underneath each other
+	WWT_SCROLLBAR,  ///< Vertical scrollbar
+	WWT_FRAME,      ///< Frame
+	WWT_CAPTION,    ///< Window caption (window title between closebox and stickybox)
+
+	WWT_HSCROLLBAR, ///< Horizontal scrollbar
+	WWT_STICKYBOX,  ///< Sticky box (normally at top-right of a window)
 	WWT_SCROLL2BAR, ///< 2nd vertical scrollbar
-	WWT_RESIZEBOX,
-	WWT_CLOSEBOX,
+	WWT_RESIZEBOX,  ///< Resize box (normally at bottom-right of a window)
+	WWT_CLOSEBOX,   ///< Close box (at top-left of a window)
 	WWT_DROPDOWN,   ///< Raised drop down list (regular)
 	WWT_DROPDOWNIN, ///< Inset drop down list (used on game options only)
 	WWT_EDITBOX,    ///< a textbox for typing (don't forget to call ShowOnScreenKeyboard() when clicked)
@@ -465,18 +514,21 @@
 
 #define WIDGETS_END WWT_LAST,   RESIZE_NONE,     0,     0,     0,     0,     0, 0, STR_NULL
 
+/**
+ * Window flags
+ */
 enum WindowFlags {
-	WF_TIMEOUT_SHL       = 0,
-	WF_TIMEOUT_MASK      = 7,
-	WF_DRAGGING          = 1 <<  3,
-	WF_SCROLL_UP         = 1 <<  4,
-	WF_SCROLL_DOWN       = 1 <<  5,
-	WF_SCROLL_MIDDLE     = 1 <<  6,
+	WF_TIMEOUT_SHL       = 0,       ///< Window timeout counter shift
+	WF_TIMEOUT_MASK      = 7,       ///< Window timeout counter bit mask (3 bits), @see WF_TIMEOUT_SHL
+	WF_DRAGGING          = 1 <<  3, ///< Window is being dragged
+	WF_SCROLL_UP         = 1 <<  4, ///< Upper scroll button has been pressed, @see ScrollbarClickHandler()
+	WF_SCROLL_DOWN       = 1 <<  5, ///< Lower scroll button has been pressed, @see ScrollbarClickHandler()
+	WF_SCROLL_MIDDLE     = 1 <<  6, ///< Scrollbar scrolling, @see ScrollbarClickHandler()
 	WF_HSCROLL           = 1 <<  7,
 	WF_SIZING            = 1 <<  8,
-	WF_STICKY            = 1 <<  9,
+	WF_STICKY            = 1 <<  9, ///< Window is made sticky by user
 
-	WF_DISABLE_VP_SCROLL = 1 << 10,
+	WF_DISABLE_VP_SCROLL = 1 << 10, ///< Window does not do autoscroll, @see HandleAutoscroll()
 
 	WF_WHITE_BORDER_ONE  = 1 << 11,
 	WF_WHITE_BORDER_MASK = 1 << 12 | WF_WHITE_BORDER_ONE,
@@ -487,11 +539,6 @@
 void CallWindowEventNP(Window *w, int event);
 void CallWindowTickEvent();
 
-/**
- * Marks the window as dirty for repaint.
- *
- * @ingroup dirty
- */
 void SetWindowDirty(const Window *w);
 void SendWindowMessage(WindowClass wnd_class, WindowNumber wnd_num, int msg, int wparam, int lparam);
 void SendWindowMessageClass(WindowClass wnd_class, int msg, int wparam, int lparam);
@@ -582,16 +629,8 @@
 
 void ScrollbarClickHandler(Window *w, const Widget *wi, int x, int y);
 
-/** Evenly distribute some widgets when resizing horizontally (often a button row)
- *  The widgets are presumed to be in a line and numberef from left to right (without gaps)
- * @param w widow to modify
- * @param left The leftmost widget to resize
- * @param right The rightmost widget to resize. Since right side of it is used, remember to set it to RESIZE_RIGHT
- */
 void ResizeButtons(Window *w, byte left, byte right);
 
-/** Resize a widget an shuffle other widgets around to fit.
- */
 void ResizeWindowForWidget(Window *w, int widget, int delta_x, int delta_y);