Ermm well first I use 'engine_open' to load the engine and then once the 'hWnd' variable is available, I use some win32 functions to embed the engine into my form.

Whenever I want to interact with the engine I use a seperate function (IEnumerable type) and call 'Scheduler.AddEventVoid(FunctionName)'.

So yes there is probably the 'engine' thread and the 'form' thread. I have however used 'yeild return Scheduler.PROC_MODE.PROC_EARLIEST' at the beginning of most functions. I thought this would allow a 'gap' into the engine processing.

There does seem to be some synchronisation issue though, because it is a very random bug.

You could maybe re-create this scenario but using the 'windows embed' demo I submitted, and from the form try to change something in the engine multiple times, like a random screen color, etc; to see if you get synchronisation problems.