if (gtk_math_view_get_action(math_view) != NULL) {
printf("click event!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\n"); if (gtk_math_view_get_action(math_view) != NULL)
clicked(GtkMathView* math_view, gpointer user_data){  if (gtk_math_view_get_action(math_view) != NULL) {    gtk_math_view_action_toggle(math_view);  }}