Index: constraint_gui.c
===================================================================
--- constraint_gui.c	(revision 21462)
+++ constraint_gui.c	(revision 21463)
@@ -199,9 +199,11 @@
 int constraint_gui(void)
 {
 	const char *tab_names[] = {"line", "move", NULL};
+	pcb_hid_dad_buttons_t clbtn[] = {{"Close", 0}, {NULL, 0}};
 	if (cnstgui_ctx.active)
 		return 0; /* do not open another */
 
+	PCB_DAD_BEGIN_VBOX(cnstgui_ctx.dlg);
 	PCB_DAD_BEGIN_TABBED(cnstgui_ctx.dlg, tab_names);
 
 		/* line */
@@ -315,6 +317,8 @@
 		PCB_DAD_END(cnstgui_ctx.dlg);
 
 	PCB_DAD_END(cnstgui_ctx.dlg);
+	PCB_DAD_BUTTON_CLOSES(cnstgui_ctx.dlg, clbtn);
+	PCB_DAD_END(cnstgui_ctx.dlg);
 
 	/* set up the context */
 	cnstgui_ctx.active = 1;