+ VALID_WINDOW(win, return);
+ g_return_if_fail(win != NULL);
+ g_return_if_fail(win->mouse_click_handler != 0);
+ g_return_if_fail(win->type != wintype_TextBuffer || win->type != wintype_TextGrid);
+
+ g_signal_handler_block( G_OBJECT(win->widget), win->mouse_click_handler );
+}
+
+/* Internal function: General callback for signal button-release-event on a
+ * text buffer or text grid window. Used for detecting clicks on hyperlinks.
+ * Blocked when not in use.
+ */
+gboolean
+on_window_button_release_event(GtkWidget *widget, GdkEventButton *event, winid_t win)
+{
+ printf("Click on (%f,%f)\n", event->x, event->y);
+ return TRUE;