Hi, In the following code only processInit and processClose get ever called, other callbacks are *never* invoked. Is this known problem? Do I miss something obvious? How do I get the handle of main window? Here is the code: module Main where import Graphics.UI.ObjectIO processAttributes = [ ProcessActivate processActivate , ProcessDeactivate processDeactivate , ProcessClose processClose , ProcessOpenFiles processOpenFiles -- , ProcessWindowPos ItemPos -- , ProcessWindowSize Size , ProcessWindowResize processWindowResize --, ProcessToolbar [ToolbarItem ps] -- , ProcessNoWindowMenu ] processInit ps = do liftIO $ putStrLn "processInit" return ps processActivate ps = do liftIO $ putStrLn "processActivate" return ps processDeactivate ps = do liftIO $ putStrLn "processDeactivate" return ps processClose ps = do liftIO $ putStrLn "processClose" closeProcess ps processOpenFiles files ps = do liftIO $ putStrLn ("processOpenFiles " ++ show files) return ps processWindowResize oldsize newsize ps = do liftIO $ putStrLn ("processWindowResize" ++ show newsize) return ps main = do startIO SDI () processInit processAttributes -- Pozdrawiam, Regards, Gracjan