Index: src/window.cpp
===================================================================
--- src/window.cpp	(revision 27146)
+++ src/window.cpp	(working copy)
@@ -87,12 +87,10 @@
 char *_windows_file;
 
 /** Window description constructor. */
-WindowDesc::WindowDesc(WindowPosition def_pos, const char *ini_key, int16 def_width, int16 def_height,
+WindowDesc::WindowDesc(WindowPosition def_pos, const char *ini_key, int16 def_width_trad, int16 def_height_trad,
 			WindowClass window_class, WindowClass parent_class, uint32 flags,
 			const NWidgetPart *nwid_parts, int16 nwid_length, HotkeyList *hotkeys) :
 	default_pos(def_pos),
-	default_width(def_width),
-	default_height(def_height),
 	cls(window_class),
 	parent_cls(parent_class),
 	ini_key(ini_key),
@@ -102,7 +100,9 @@
 	hotkeys(hotkeys),
 	pref_sticky(false),
 	pref_width(0),
-	pref_height(0)
+	pref_height(0),
+	default_width_trad(def_width_trad),
+	default_height_trad(def_height_trad)
 {
 	if (_window_descs == NULL) _window_descs = new SmallVector<WindowDesc*, 16>();
 	*_window_descs->Append() = this;
@@ -113,6 +113,16 @@
 	_window_descs->Erase(_window_descs->Find(this));
 }
 
+int16 WindowDesc::GetDefaultWidth() const
+{
+	return this->pref_width != 0 ? this->pref_width : ScaleGUITrad(this->default_width_trad);
+}
+
+int16 WindowDesc::GetDefaultHeight() const
+{
+	return this->pref_height != 0 ? this->pref_height : ScaleGUITrad(this->default_height_trad);
+}
+
 /**
  * Load all WindowDesc settings from _windows_file.
  */
Index: src/window_gui.h
===================================================================
--- src/window_gui.h	(revision 27146)
+++ src/window_gui.h	(working copy)
@@ -167,15 +167,13 @@
  */
 struct WindowDesc : ZeroedMemoryAllocator {
 
-	WindowDesc(WindowPosition default_pos, const char *ini_key, int16 def_width, int16 def_height,
+	WindowDesc(WindowPosition default_pos, const char *ini_key, int16 def_width_trad, int16 def_height_trad,
 			WindowClass window_class, WindowClass parent_class, uint32 flags,
 			const NWidgetPart *nwid_parts, int16 nwid_length, HotkeyList *hotkeys = NULL);
 
 	~WindowDesc();
 
 	WindowPosition default_pos;    ///< Preferred position of the window. @see WindowPosition()
-	int16 default_width;           ///< Preferred initial width of the window.
-	int16 default_height;          ///< Preferred initial height of the window.
 	WindowClass cls;               ///< Class of the window, @see WindowClass.
 	WindowClass parent_cls;        ///< Class of the parent window. @see WindowClass
 	const char *ini_key;           ///< Key to store window defaults in openttd.cfg. \c NULL if nothing shall be stored.
@@ -188,13 +186,16 @@
 	int16 pref_width;              ///< User-preferred width of the window. Zero if unset.
 	int16 pref_height;             ///< User-preferred height of the window. Zero if unset.
 
-	int16 GetDefaultWidth() const { return this->pref_width != 0 ? this->pref_width : this->default_width; }
-	int16 GetDefaultHeight() const { return this->pref_height != 0 ? this->pref_height : this->default_height; }
+	int16 GetDefaultWidth() const;
+	int16 GetDefaultHeight() const;
 
 	static void LoadFromConfig();
 	static void SaveToConfig();
 
 private:
+	int16 default_width_trad;      ///< Preferred initial width of the window (pixels at 1x zoom).
+	int16 default_height_trad;     ///< Preferred initial height of the window (pixels at 1x zoom).
+
 	/**
 	 * Dummy private copy constructor to prevent compilers from
 	 * copying the structure, which fails due to _window_descs.