Tor Lillqvist asked me to open a new bug report for this, so here it is.

This bug is present on Windows, GTK+ version 2.16.6, when using
gtk_file_chooser_button.

Every time you click on the button and then close the dialog, it uses more
memory and opens more handles.

Code:

#include <gtk/gtk.h>
int main (int argc, char **argv) {
  GtkWidget *window, *chooser1;
  gtk_init(&argc, &argv);
  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  chooser1 = gtk_file_chooser_button_new ("Open",
GTK_FILE_CHOOSER_ACTION_OPEN);
  gtk_container_add (GTK_CONTAINER (window), chooser1);
  gtk_widget_show_all (window);
  gtk_main();
  return 0;
}