3 files changed, 22 insertions, 3 deletions
diff --git a/src/viewport.cpp b/src/viewport.cpp
index 96dbe753c..b9636ca11 100644
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -32,8 +32,22 @@
 
 ZoomLevel _saved_scrollpos_zoom;
 
-/* XXX - maximum viewports is maximum windows - 2 (main toolbar + status bar) */
-static ViewPort _viewports[25 - 2];
+/**
+ * The maximum number of viewports depends on the maximum number
+ * of windows. Technically is could be the maximum number of
+ * windows, but there is always at least one window that does
+ * not need a viewport. Not having 'support' for that viewport
+ * saves some time and memory.
+ * For the introduction GUI and create game GUIs there is no
+ * need for more than one viewport, however in the normal game
+ * and scenario editor one can make a lot of viewports. For the
+ * normal game one always has a main toolbar and a status bar,
+ * however the statusbar does not exist on the scenario editor.
+ *
+ * This means that we can only safely assume that there is one
+ * window without viewport.
+ */
+static ViewPort _viewports[MAX_NUMBER_OF_WINDOWS - 1];
 static uint32 _active_viewports;    ///< bitmasked variable where each bit signifies if a viewport is in use or not
 assert_compile(lengthof(_viewports) < sizeof(_active_viewports) * 8);
 
diff --git a/src/window.cpp b/src/window.cpp
index 958eb4475..f5b9ac041 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -22,7 +22,7 @@
 /* delta between mouse cursor and upper left corner of dragged window */
 static Point _drag_delta;
 
-static Window _windows[25];
+static Window _windows[MAX_NUMBER_OF_WINDOWS];
 Window *_z_windows[lengthof(_windows)];
 Window **_last_z_window; ///< always points to the next free space in the z-array
 
diff --git a/src/window.h b/src/window.h
index 1fae1a5ca..11086e64b 100644
--- a/src/window.h
+++ b/src/window.h
@@ -14,6 +14,11 @@
 #include "vehicle.h"
 #include "viewport.h"
 
+/**
+ * The maximum number of windows that can be opened.
+ */
+static const int MAX_NUMBER_OF_WINDOWS = 25;
+
 struct WindowEvent;
 
 typedef void WindowProc(Window *w, WindowEvent *e);