Your solution was right, thank you very well. But I have problem with way to set sensitive agian, because I use pull down menu from button_press_event. If I used sensitive(0), no signal_handler was called and no sensitive(1) called too. Menu trick is not in my previouse attachment, but it is in my programm, and used not only to permit or restrict selection in clist. In ths case of working signal_emit_stop_by_name() it's very simple to do. Thank you for your advise. Any suggestion, please.
I've extracted your example and discovered that stop_emit_by_name works fine there. I've just added to clist.pl second signal handler and debug printing from withing signal handlers. set_selectable() method may be used as well if you wish to change standard selection policy of CList.
Best regards Pavel.