--- a/ui/gtk/container.h	Sat Jan 23 20:47:07 2016 +0100
+++ b/ui/gtk/container.h	Sat Jan 23 23:44:41 2016 +0100
@@ -89,8 +89,8 @@
     UiContainer container;
 } UiTabViewContainer;
 
-GtkWidget* ui_gtk_vbox_new();
-GtkWidget* ui_gtk_hbox_new();
+GtkWidget* ui_gtk_vbox_new(int spacing);
+GtkWidget* ui_gtk_hbox_new(int spacing);
 
 UiContainer* ui_frame_container(UiObject *obj, GtkWidget *frame);
 void ui_frame_container_add(UiContainer *ct, GtkWidget *widget, UiBool fill);