diff --git a/src/gtk/gtkmain.cpp b/src/gtk/gtkmain.cpp
index 73b6036..386e970 100644
--- a/src/gtk/gtkmain.cpp
+++ b/src/gtk/gtkmain.cpp
@@ -55,10 +55,7 @@
 #include "../unix/gloffscreen.h"
 
 #ifdef HAVE_SPACEWARE
-#   include <spnav.h>
-#   ifndef SI_APP_FIT_BUTTON
-#       define SI_APP_FIT_BUTTON 31
-#   endif
+#include <spnav.h>
 #endif
 
 namespace SolveSpace {
@@ -1523,7 +1520,7 @@ static GdkFilterReturn GdkSpnavFilter(GdkXEvent *gxevent, GdkEvent *, gpointer)
             break;
 
         case SPNAV_EVENT_BUTTON:
-            if(!sev.button.press && sev.button.bnum == SI_APP_FIT_BUTTON) {
+            if(!sev.button.press && sev.button.bnum == 0) {
                 SS.GW.SpaceNavigatorButtonUp();
             }
             break;