Hello list, i managed to build a new host windows plugin which currently including - window management - event handling - display/draw support The difference between old plugin, that for each host window an image always keeping own instance of HostWindow and provides an easy and fast way to translate a window hanlde (reported in events) to a corresponding HostWindow instance. A plugin, instead of operating with a raw OS window handles, keeping own list of open windows and lets language side operate with index in that list. Now, since all window handles is ordered and start counting from 0 , all we need is to keep a WeakArray and that array at: windowHandle can return us the corresponding HostWindow instance. This will allow to direct event handling to a proper HostWindow instance. That's where the fun begins. But! A host window is not a Form or DisplayScreen. It having a simple primitive which , like in old plugin, allows to blit a portion of form to a host window surface. Also, a plugin generates events to notify image about different things like window dimensions has changed or portion of screen need to be redrawn. What i would like to ask, is how to wire Form (or some DisplayScreen subclass) with HostWindow. Obviously, a HostWindow acts as backend , and don't needs to know anything about who wants to draw on it or listen for events. I need an advice , how to bind couple of events, which HostWindow should handle, and report them further to something which controls what to draw in it. Current 'interesting' number of events is quite small: - a window size has changed (and Form/DisplayScreen need to resync with new size, obviously) - a portion of window should be updated/redrawn (and Form/DisplayScreen needs to repaint the damaged region, obviously) there, of course will be more, but first things first :) What you think is the best way for reporting such events? -- Best regards, Igor Stasenko AKA sig.