diff --git a/src/gtk/toplevel.cpp b/src/gtk/toplevel.cpp
index f20f59c82d..b29852875a 100644
--- a/src/gtk/toplevel.cpp
+++ b/src/gtk/toplevel.cpp
@@ -38,20 +38,6 @@
     #include <X11/Xatom.h>  // XA_CARDINAL
     #include "wx/unix/utilsx11.h"
 #endif
-#ifdef GDK_WINDOWING_WAYLAND
-    #include <gdk/gdkwayland.h>
-    #define HAS_CLIENT_DECOR
-#endif
-#ifdef GDK_WINDOWING_MIR
-    extern "C" {
-    #include <gdk/gdkmir.h>
-    }
-    #define HAS_CLIENT_DECOR
-#endif
-#ifdef GDK_WINDOWING_BROADWAY
-    #include <gdk/gdkbroadway.h>
-    #define HAS_CLIENT_DECOR
-#endif
 
 #include "wx/gtk/private.h"
 #include "wx/gtk/private/gtk2-compat.h"
@@ -80,25 +66,29 @@ static enum {
 static bool gs_decorCacheValid;
 #endif
 
-#ifdef HAS_CLIENT_DECOR
+#ifdef __WXGTK3__
 static bool HasClientDecor(GtkWidget* widget)
 {
-    GdkDisplay* display = gtk_widget_get_display(widget);
-#ifdef GDK_WINDOWING_WAYLAND
-    if (GDK_IS_WAYLAND_DISPLAY(display))
-        return true;
-#endif
-#ifdef GDK_WINDOWING_MIR
-    if (GDK_IS_MIR_DISPLAY(display))
-        return true;
-#endif
-#ifdef GDK_WINDOWING_BROADWAY
-    if (GDK_IS_BROADWAY_DISPLAY(display))
-        return true;
-#endif
+    static bool has;
+    static bool once;
+    if (!once)
+    {
+        once = true;
+        GdkDisplay* display = gtk_widget_get_display(widget);
+        const char* name = g_type_name(G_TYPE_FROM_INSTANCE(display));
+        has =
+            strcmp(name, "GdkWaylandDisplay") == 0 ||
+            strcmp(name, "GdkMirDisplay") == 0 ||
+            strcmp(name, "GdkBroadwayDisplay") == 0;
+    }
+    return has;
+}
+#else
+static inline bool HasClientDecor(GtkWidget*)
+{
     return false;
 }
-#endif // HAS_CLIENT_DECOR
+#endif
 
 //-----------------------------------------------------------------------------
 // RequestUserAttention related functions
@@ -253,7 +243,6 @@ size_allocate(GtkWidget*, GtkAllocation* alloc, wxTopLevelWindowGTK* win)
         GtkAllocation a;
         gtk_widget_get_allocation(win->m_widget, &a);
         wxSize size(a.width, a.height);
-#ifdef HAS_CLIENT_DECOR
         if (HasClientDecor(win->m_widget))
         {
             GtkAllocation a2;
@@ -266,7 +255,6 @@ size_allocate(GtkWidget*, GtkAllocation* alloc, wxTopLevelWindowGTK* win)
             win->GTKUpdateDecorSize(decorSize);
         }
         else
-#endif
         {
             size.x += win->m_decorSize.left + win->m_decorSize.right;
             size.y += win->m_decorSize.top + win->m_decorSize.bottom;
@@ -740,9 +728,9 @@ bool wxTopLevelWindowGTK::Create( wxWindow *parent,
 
         if ( style & wxCAPTION )
             m_gdkDecor |= GDK_DECOR_TITLE;
-#if defined(GDK_WINDOWING_WAYLAND) && GTK_CHECK_VERSION(3,10,0)
+#if GTK_CHECK_VERSION(3,10,0)
         else if (
-            GDK_IS_WAYLAND_DISPLAY(gtk_widget_get_display(m_widget)) &&
+            strcmp("GdkWaylandDisplay", g_type_name(G_TYPE_FROM_INSTANCE(gtk_widget_get_display(m_widget)))) == 0 &&
             gtk_check_version(3,10,0) == NULL)
         {
             gtk_window_set_titlebar(GTK_WINDOW(m_widget), gtk_header_bar_new());
@@ -1080,9 +1068,7 @@ void wxTopLevelWindowGTK::DoMoveWindow(int WXUNUSED(x), int WXUNUSED(y), int WXU
 void wxTopLevelWindowGTK::GTKDoGetSize(int *width, int *height) const
 {
     wxSize size(m_width, m_height);
-#ifdef HAS_CLIENT_DECOR
     if (!HasClientDecor(m_widget))
-#endif
     {
         size.x -= m_decorSize.left + m_decorSize.right;
         size.y -= m_decorSize.top + m_decorSize.bottom;
@@ -1239,14 +1225,12 @@ void wxTopLevelWindowGTK::DoSetSizeHints( int minW, int minH,
     hints.max_height = INT_MAX / 16;
     int decorSize_x;
     int decorSize_y;
-#ifdef HAS_CLIENT_DECOR
     if (HasClientDecor(m_widget))
     {
         decorSize_x = 0;
         decorSize_y = 0;
     }
     else
-#endif
     {
         decorSize_x = m_decorSize.left + m_decorSize.right;
         decorSize_y = m_decorSize.top + m_decorSize.bottom;
@@ -1282,13 +1266,11 @@ void wxTopLevelWindowGTK::GTKUpdateDecorSize(const DecorSize& decorSize)
     if (!IsMaximized() && !IsFullScreen())
         GetCachedDecorSize() = decorSize;
 
-#ifdef HAS_CLIENT_DECOR
     if (HasClientDecor(m_widget))
     {
         m_decorSize = decorSize;
         return;
     }
-#endif
 #ifdef GDK_WINDOWING_X11
     if (m_updateDecorSize && memcmp(&m_decorSize, &decorSize, sizeof(DecorSize)))
     {