diff --git a/docs/changes.txt b/docs/changes.txt
index a1cbb3d37e..147a420e2f 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -95,8 +95,6 @@ All (GUI):
 
 - wxGraphicsContext implementations now all have the pixel's center at (0.5,0.5), 
   avoiding differences in anti-aliasing between platforms.
-- Added sizer.desktopmargin.x/y system options so wxSizer::Fit can allow
-  for decorations.
 
 wxMSW:
 
@@ -109,6 +107,8 @@ wxGTK:
   a background colour bug in the gtk-qt theme under KDE.
 - wxSystemSettings::GetColour(wxSYS_COLOUR_WINDOW) now returns the background
   colour of text controls.
+- Added gtk.desktopmargin.x/y system options to allow windows to fit the desktop
+  when Xinerama is not available.
 
 wxMac:
 
diff --git a/docs/latex/wx/sysopt.tex b/docs/latex/wx/sysopt.tex
index 8958d9bd0b..502b957bc6 100644
--- a/docs/latex/wx/sysopt.tex
+++ b/docs/latex/wx/sysopt.tex
@@ -45,6 +45,8 @@ used if wider fonts selection is more important than higher quality.}
 \twocolitem{{\bf Option}}{{\bf Value}}
 \twocolitem{gtk.window.force-background-colour}{If 1, the backgrounds of windows with the wxBG\_STYLE\_COLOUR background style are cleared forcibly instead
 of relying on the underlying GTK+ window colour. This works around a display problem when running applications under KDE with the gtk-qt theme installed (0.6 and below).}
+\twocolitem{sizer.desktopmargin.x}{The horizontal margin to subtract from the desktop size when Xinerama is not available.}
+\twocolitem{sizer.desktopmargin.y}{The vertical margin to subtract from the desktop size when Xinerama is not available.}
 \end{twocollist}
 
 \wxheading{Mac}
@@ -80,15 +82,6 @@ A reasonable default is used if not specified.}
 \twocolitem{motif.largebuttons}{If 1, uses a bigger default size for wxButtons.}
 \end{twocollist}
 
-\wxheading{All}
-
-\twocolwidtha{7cm}
-\begin{twocollist}\itemsep=0pt
-\twocolitem{{\bf Option}}{{\bf Value}}
-\twocolitem{sizer.desktopmargin.x}{The horizontal margin to subtract from the desktop size when computing the maximum top-level window size in wxSizer::Fit.}
-\twocolitem{sizer.desktopmargin.y}{The vertical margin to subtract from the desktop size when computing the maximum top-level window size in wxSizer::Fit.}
-\end{twocollist}
-
 The compile-time option to include or exclude this functionality
 is wxUSE\_SYSTEM\_OPTIONS.
 
diff --git a/src/common/sizer.cpp b/src/common/sizer.cpp
index 2a4581396a..c4ea7ad458 100644
--- a/src/common/sizer.cpp
+++ b/src/common/sizer.cpp
@@ -31,10 +31,6 @@
     #include "wx/toplevel.h"
 #endif // WX_PRECOMP
 
-#if wxUSE_SYSTEM_OPTIONS
-#include "wx/sysopt.h"
-#endif
-
 #include "wx/listimpl.cpp"
 
 #if WXWIN_COMPATIBILITY_2_4
@@ -796,13 +792,6 @@ wxSize wxSizer::Fit( wxWindow *window )
             }
 
             sizeMax = wxDisplay(disp).GetClientArea().GetSize();
-
-#if wxUSE_SYSTEM_OPTIONS
-            int marginX = wxSystemOptions::GetOptionInt(wxT("sizer.desktopmargin.x"));
-            int marginY = wxSystemOptions::GetOptionInt(wxT("sizer.desktopmargin.y"));
-            sizeMax.x -= marginX;
-            sizeMax.y -= marginY;
-#endif
         }
     }
 
diff --git a/src/gtk/utilsgtk.cpp b/src/gtk/utilsgtk.cpp
index c07fc6170d..9c4934db37 100644
--- a/src/gtk/utilsgtk.cpp
+++ b/src/gtk/utilsgtk.cpp
@@ -18,10 +18,9 @@
     #include "wx/log.h"
 #endif
 
+#include "wx/sysopt.h"
 #include "wx/apptrait.h"
-
 #include "wx/process.h"
-
 #include "wx/unix/execute.h"
 
 #ifdef __WXDEBUG__
@@ -140,8 +139,11 @@ void *wxGetDisplay()
 
 void wxDisplaySize( int *width, int *height )
 {
-    if (width) *width = gdk_screen_width();
-    if (height) *height = gdk_screen_height();
+    int marginX = wxSystemOptions::GetOptionInt(wxT("gtk.desktopmargin.x"));
+    int marginY = wxSystemOptions::GetOptionInt(wxT("gtk.desktopmargin.y"));
+
+    if (width) *width = gdk_screen_width() - marginX;
+    if (height) *height = gdk_screen_height() - marginY;
 }
 
 void wxDisplaySizeMM( int *width, int *height )