diff --git a/win32/zoitechat.props b/win32/zoitechat.props
index df94cb00..cb8a70ad 100644
--- a/win32/zoitechat.props
+++ b/win32/zoitechat.props
@@ -14,7 +14,7 @@
 
 		<!-- G_DISABLE_DEPRECATED is unfeasible due to g_completion_* -->
 		<!-- must be buildable with GSEAL_ENABLE in the future, xtext, setup, and chanview-tabs stand in the way -->
-		<OwnFlags>GTK_DISABLE_DEPRECATED;GDK_PIXBUF_DISABLE_DEPRECATED;G_DISABLE_SINGLE_INCLUDES;GDK_PIXBUF_DISABLE_SINGLE_INCLUDES;GTK_DISABLE_SINGLE_INCLUDES;HAVE_X509_GET_SIGNATURE_NID;HAVE_SSL_CTX_GET_SSL_METHOD;DEFAULT_CERT_FILE="cert.pem";HAVE_STRTOULL;strtoull=_strtoui64;strcasecmp=stricmp;strncasecmp=strnicmp;__inline__=__inline</OwnFlags>
+		<OwnFlags>GTK_DISABLE_DEPRECATED;GDK_PIXBUF_DISABLE_DEPRECATED;G_DISABLE_SINGLE_INCLUDES;GDK_PIXBUF_DISABLE_SINGLE_INCLUDES;GTK_DISABLE_SINGLE_INCLUDES;HAVE_X509_GET_SIGNATURE_NID;HAVE_SSL_CTX_GET_SSL_METHOD;DEFAULT_CERT_FILE="cert.pem";HAVE_STRTOULL;strtoull=_strtoui64;strcasecmp=stricmp;strncasecmp=strnicmp;__inline__=__inline;$(GtkDefines)</OwnFlags>
 		<!-- FIXME: Add ability to use debug builds -->
 		<GtkPlatform Condition="'$(PlatformName)'=='Win32'">x86</GtkPlatform>
 		<GtkPlatform Condition="'$(GtkPlatform)'==''">$(PlatformName)</GtkPlatform>
@@ -37,6 +37,8 @@
 		<LuaLib Condition="'$(LuaLib)'==''">lua51</LuaLib>
 		<Glib>$(DepsRoot)\include\glib-2.0;$(DepsRoot)\lib\glib-2.0\include;$(DepsRoot)\include\libxml2</Glib>
         <UsingGtk3 Condition="Exists('$(DepsRoot)\\include\\gtk-3.0\\gtk\\gtk.h')">true</UsingGtk3>
+        <GtkDefines Condition="'$(UsingGtk3)'=='true'">HAVE_GTK3</GtkDefines>
+        <GtkDefines Condition="'$(UsingGtk3)'!='true'">HAVE_GTK2</GtkDefines>
         <Gtk2>$(DepsRoot)\include\gtk-2.0;$(DepsRoot)\lib\gtk-2.0\include</Gtk2>
         <Gtk3>$(DepsRoot)\include\gtk-3.0;$(DepsRoot)\lib\gtk-3.0\include</Gtk3>
         <GtkCommon>$(DepsRoot)\include\atk-1.0;$(DepsRoot)\include\cairo;$(DepsRoot)\include\pango-1.0;$(DepsRoot)\include\gdk-pixbuf-2.0;$(DepsRoot)\include\harfbuzz</GtkCommon>
@@ -132,3 +134,4 @@
 
 
 
+