diff --git a/configure b/configure
index ed4e4a4ce5..ec73c2b1d0 100755
--- a/configure
+++ b/configure
@@ -24315,6 +24315,8 @@ libraries returned by 'pkg-config gtk+-2.0 --libs' or 'gtk-config
         esac
 
         if test "$WXGTK3" = 1; then
+            $as_echo "#define __WXGTK220__ 1" >>confdefs.h
+
             $as_echo "#define __WXGTK218__ 1" >>confdefs.h
 
             $as_echo "#define __WXGTK210__ 1" >>confdefs.h
@@ -24325,47 +24327,13 @@ libraries returned by 'pkg-config gtk+-2.0 --libs' or 'gtk-config
             CFLAGS="$wx_cv_cflags_gtk $CFLAGS"
             LIBS="$LIBS $wx_cv_libs_gtk"
 
-                        { $as_echo "$as_me:${as_lineno-$LINENO}: checking if GTK+ is version >= 2.18" >&5
-$as_echo_n "checking if GTK+ is version >= 2.18... " >&6; }
-            cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-                            #include <gtk/gtk.h>
-
-int
-main ()
-{
-
-                            #if !GTK_CHECK_VERSION(2,18,0)
-                            Not GTK+ 2.18
-                            #endif
-
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
-
-                            $as_echo "#define __WXGTK218__ 1" >>confdefs.h
-
-                            $as_echo "#define __WXGTK210__ 1" >>confdefs.h
-
-                            { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-$as_echo "yes" >&6; }
-                            ac_wxgtk218=1
 
+            { $as_echo "$as_me:${as_lineno-$LINENO}: checking if GTK+ is version >= 2.20" >&5
+$as_echo_n "checking if GTK+ is version >= 2.20... " >&6; }
+if ${wx_cv_gtk220+:} false; then :
+  $as_echo_n "(cached) " >&6
 else
 
-                            { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-                            ac_wxgtk218=0
-
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-
-            if test "$ac_wxgtk218" = 0; then
-                                { $as_echo "$as_me:${as_lineno-$LINENO}: checking if GTK+ is version >= 2.10" >&5
-$as_echo_n "checking if GTK+ is version >= 2.10... " >&6; }
                 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -24375,8 +24343,8 @@ int
 main ()
 {
 
-                                #if !GTK_CHECK_VERSION(2,10,0)
-                                Not GTK+ 2.10
+                                #if !GTK_CHECK_VERSION(2,20,0)
+                                Not GTK+ 2.20
                                 #endif
 
   ;
@@ -24384,21 +24352,102 @@ main ()
 }
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-
-                                $as_echo "#define __WXGTK210__ 1" >>confdefs.h
-
-                                { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-$as_echo "yes" >&6; }
-                                ac_wxgtk210=1
-
+  wx_cv_gtk220=yes
 else
-
-                                { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-                                ac_wxgtk210=0
+  wx_cv_gtk220=no
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $wx_cv_gtk220" >&5
+$as_echo "$wx_cv_gtk220" >&6; }
+
+            if test "$wx_cv_gtk220" = "yes"; then
+                $as_echo "#define __WXGTK220__ 1" >>confdefs.h
+
+                wx_cv_gtk218=yes
+            else
+                { $as_echo "$as_me:${as_lineno-$LINENO}: checking if GTK+ is version >= 2.18" >&5
+$as_echo_n "checking if GTK+ is version >= 2.18... " >&6; }
+if ${wx_cv_gtk218+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
+                    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+                                    #include <gtk/gtk.h>
+
+int
+main ()
+{
+
+                                    #if !GTK_CHECK_VERSION(2,18,0)
+                                    Not GTK+ 2.18
+                                    #endif
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  wx_cv_gtk218=yes
+else
+  wx_cv_gtk218=no
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $wx_cv_gtk218" >&5
+$as_echo "$wx_cv_gtk218" >&6; }
+            fi
+
+            if test "$wx_cv_gtk218" = "yes"; then
+                $as_echo "#define __WXGTK218__ 1" >>confdefs.h
+
+                wx_cv_gtk210=yes
+            else
+                { $as_echo "$as_me:${as_lineno-$LINENO}: checking if GTK+ is version >= 2.10" >&5
+$as_echo_n "checking if GTK+ is version >= 2.10... " >&6; }
+if ${wx_cv_gtk210+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
+                    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+                                    #include <gtk/gtk.h>
+
+int
+main ()
+{
+
+                                    #if !GTK_CHECK_VERSION(2,10,0)
+                                    Not GTK+ 2.10
+                                    #endif
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  wx_cv_gtk210=yes
+else
+  wx_cv_gtk210=no
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $wx_cv_gtk210" >&5
+$as_echo "$wx_cv_gtk210" >&6; }
+            fi
+
+            if test "$wx_cv_gtk210" = "yes"; then
+                $as_echo "#define __WXGTK210__ 1" >>confdefs.h
+
             fi
 
             CFLAGS="$save_CFLAGS"
diff --git a/configure.in b/configure.in
index 5be016ab7a..208f03896c 100644
--- a/configure.in
+++ b/configure.in
@@ -2785,6 +2785,7 @@ libraries returned by 'pkg-config gtk+-2.0 --libs' or 'gtk-config
         esac
 
         if test "$WXGTK3" = 1; then
+            AC_DEFINE(__WXGTK220__)
             AC_DEFINE(__WXGTK218__)
             AC_DEFINE(__WXGTK210__)
         elif test "$WXGTK2" = 1; then
@@ -2793,47 +2794,66 @@ libraries returned by 'pkg-config gtk+-2.0 --libs' or 'gtk-config
             CFLAGS="$wx_cv_cflags_gtk $CFLAGS"
             LIBS="$LIBS $wx_cv_libs_gtk"
 
-            dnl test if we have at least GTK+ 2.18:
-            AC_MSG_CHECKING([if GTK+ is version >= 2.18])
-            AC_TRY_COMPILE([
-                            #include <gtk/gtk.h>
-                           ],
-                           [
-                            #if !GTK_CHECK_VERSION(2,18,0)
-                            Not GTK+ 2.18
-                            #endif
-                           ],
-                           [
-                            AC_DEFINE(__WXGTK218__)
-                            AC_DEFINE(__WXGTK210__)
-                            AC_MSG_RESULT([yes])
-                            ac_wxgtk218=1
-                           ],
-                           [
-                            AC_MSG_RESULT([no])
-                            ac_wxgtk218=0
-                           ])
+            dnl We need to define __WXGTK2xx__ symbols for a few specific
+            dnl versions in order to be able to test for them (and hence for
+            dnl the availability of the controls which appeared only in these
+            dnl versions) from our public headers, without having to include
+            dnl gtk/gtk.h from them.
 
-            if test "$ac_wxgtk218" = 0; then
-                dnl test if we have at least GTK+ 2.10:
-                AC_MSG_CHECKING([if GTK+ is version >= 2.10])
+            AC_CACHE_CHECK([if GTK+ is version >= 2.20], wx_cv_gtk220, [
                 AC_TRY_COMPILE([
                                 #include <gtk/gtk.h>
                                ],
                                [
-                                #if !GTK_CHECK_VERSION(2,10,0)
-                                Not GTK+ 2.10
+                                #if !GTK_CHECK_VERSION(2,20,0)
+                                Not GTK+ 2.20
                                 #endif
                                ],
-                               [
-                                AC_DEFINE(__WXGTK210__)
-                                AC_MSG_RESULT([yes])
-                                ac_wxgtk210=1
-                               ],
-                               [
-                                AC_MSG_RESULT([no])
-                                ac_wxgtk210=0
-                               ])
+                               wx_cv_gtk220=yes,
+                               wx_cv_gtk220=no
+                               )
+            ])
+
+            if test "$wx_cv_gtk220" = "yes"; then
+                AC_DEFINE(__WXGTK220__)
+                wx_cv_gtk218=yes
+            else
+                AC_CACHE_CHECK([if GTK+ is version >= 2.18], wx_cv_gtk218, [
+                    AC_TRY_COMPILE([
+                                    #include <gtk/gtk.h>
+                                   ],
+                                   [
+                                    #if !GTK_CHECK_VERSION(2,18,0)
+                                    Not GTK+ 2.18
+                                    #endif
+                                   ],
+                                   wx_cv_gtk218=yes,
+                                   wx_cv_gtk218=no
+                                   )
+                ])
+            fi
+
+            if test "$wx_cv_gtk218" = "yes"; then
+                AC_DEFINE(__WXGTK218__)
+                wx_cv_gtk210=yes
+            else
+                AC_CACHE_CHECK([if GTK+ is version >= 2.10], wx_cv_gtk210, [
+                    AC_TRY_COMPILE([
+                                    #include <gtk/gtk.h>
+                                   ],
+                                   [
+                                    #if !GTK_CHECK_VERSION(2,10,0)
+                                    Not GTK+ 2.10
+                                    #endif
+                                   ],
+                                   wx_cv_gtk210=yes,
+                                   wx_cv_gtk210=no
+                                   )
+                ])
+            fi
+
+            if test "$wx_cv_gtk210" = "yes"; then
+                AC_DEFINE(__WXGTK210__)
             fi
 
             CFLAGS="$save_CFLAGS"
diff --git a/setup.h.in b/setup.h.in
index 9b49054473..1aec146871 100644
--- a/setup.h.in
+++ b/setup.h.in
@@ -65,6 +65,9 @@
 /* Define this if your version of GTK+ is greater than 2.18 */
 #undef __WXGTK218__
 
+/* Define this if your version of GTK+ is greater than 2.20 */
+#undef __WXGTK220__
+
 /* Define this if your version of GTK+ is >= 3.0 */
 #undef __WXGTK3__
 
diff --git a/setup.h_vms b/setup.h_vms
index 62e5640eef..37cdd8b9cc 100644
--- a/setup.h_vms
+++ b/setup.h_vms
@@ -101,6 +101,9 @@
 /* Define this if your version of GTK+ is greater than 2.18 */
 #undef __WXGTK218__
 
+/* Define this if your version of GTK+ is greater than 2.20 */
+#undef __WXGTK220__
+
 #include <types.h>
 typedef pid_t GPid;