--- a/ui/gtk/toolkit.c	Fri Nov 10 18:04:40 2017 +0100
+++ b/ui/gtk/toolkit.c	Sat Nov 11 08:34:06 2017 +0100
@@ -226,6 +226,11 @@
     free(userdata);
 }
 
+void ui_destroy_vardata(GtkWidget *object, UiVarEventData *data) {
+    ui_destroy_boundvar(data->obj->ctx, data->var);
+    free(data);
+}
+
 void ui_destroy_boundvar(UiContext *ctx, UiVar *var) {
     if(var->type == UI_VAR_SPECIAL) {
         free(var);