diff -up xgalaga-2.0.34/libsprite/makewindow.c~ xgalaga-2.0.34/libsprite/makewindow.c
--- xgalaga-2.0.34/libsprite/makewindow.c~	2009-09-11 08:48:44.000000000 +0200
+++ xgalaga-2.0.34/libsprite/makewindow.c	2009-09-11 08:50:50.000000000 +0200
@@ -642,6 +642,13 @@ void W_ToggleFullscreen(_win)
       }
     }
         
+    /* Warp the pointer to the upper left corner (where our fs_window is),
+       this is necessary as the: XF86VidModeSetViewPort() call below does
+       not seem to do anything on newer Xorg servers, instead the viewport
+       seems to always be centered at the last mouse cursor position. */
+    XWarpPointer(W_Display, None, XDefaultRootWindow(W_Display),
+                 0, 0, 0, 0, 0, 0);
+
     /* Switch video mode.  */
     if ((i >= 0) &&
         ((modes[i]->hdisplay != mode.hdisplay) ||