if i'm not modifying let say i do request to websocket -> sync button status -> respond received -> set button A with caption 'on' to 'off'. it would force close if i do parsing message to execute changing button from 'ON' to 'OFF' (about 10 buttons) -> SOLUTION: manually changing button caption 1 by 1 after clicking (as i knew, i did it a lot of times before, no error happened -> changing a lot buttons programatically). And lately i can't do showmessage on LAMW is it my fault or not?