diff --git a/extensions/adblock.c b/extensions/adblock.c
index 852a4b18..b35ae793 100644
--- a/extensions/adblock.c
+++ b/extensions/adblock.c
@@ -480,6 +480,11 @@ adblock_get_preferences_dialog (MidoriExtension* extension)
         GTK_STOCK_CLOSE, GTK_RESPONSE_CLOSE,
         #endif
         NULL);
+    #if GTK_CHECK_VERSION (3, 0, 0)
+    gtk_style_context_add_class (gtk_widget_get_style_context (
+        gtk_dialog_get_widget_for_response (GTK_DIALOG (dialog),
+            GTK_RESPONSE_HELP)), "help_button");
+    #endif
     content_area = gtk_dialog_get_content_area (GTK_DIALOG (dialog));
     g_signal_connect (dialog, "destroy",
                       G_CALLBACK (gtk_widget_destroyed), &dialog);
diff --git a/midori/midori-browser.c b/midori/midori-browser.c
index 1ace19fa..fae649c9 100644
--- a/midori/midori-browser.c
+++ b/midori/midori-browser.c
@@ -4752,6 +4752,11 @@ _action_clear_private_data_activate (GtkAction*     action,
             GTK_DIALOG_DESTROY_WITH_PARENT | GTK_DIALOG_NO_SEPARATOR,
             GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
             _("_Clear private data"), GTK_RESPONSE_ACCEPT, NULL);
+        #if GTK_CHECK_VERSION (3, 0, 0)
+        gtk_style_context_add_class (gtk_widget_get_style_context (
+            gtk_dialog_get_widget_for_response (GTK_DIALOG (dialog),
+                GTK_RESPONSE_ACCEPT)), "noundo");
+        #endif
         content_area = gtk_dialog_get_content_area (GTK_DIALOG (dialog));
         gtk_window_set_skip_taskbar_hint (GTK_WINDOW (dialog), FALSE);
         screen = gtk_widget_get_screen (GTK_WIDGET (browser));
diff --git a/midori/midori-searchaction.c b/midori/midori-searchaction.c
index a4efe454..a6d3dbf1 100644
--- a/midori/midori-searchaction.c
+++ b/midori/midori-searchaction.c
@@ -1305,6 +1305,11 @@ midori_search_action_get_dialog (MidoriSearchAction* search_action)
         GTK_STOCK_CLOSE, GTK_RESPONSE_CLOSE,
         #endif
         NULL);
+    #if GTK_CHECK_VERSION (3, 0, 0)
+    gtk_style_context_add_class (gtk_widget_get_style_context (
+        gtk_dialog_get_widget_for_response (GTK_DIALOG (dialog),
+            GTK_RESPONSE_HELP)), "help_button");
+    #endif
     g_signal_connect (dialog, "destroy",
                       G_CALLBACK (gtk_widget_destroyed), &search_action->dialog);
     gtk_window_set_icon_name (GTK_WINDOW (dialog), GTK_STOCK_PROPERTIES);