Hello Hristo,

Yes you are right, our application is multithreaded, but the work on the user interface is always done on the main thread.

We are using three different methods to switch the context on the main thread:

– our software is built using SmartClient Software Factory (based on CompositeUI). We are using the event aggregator asking it to switch the call on the UI thread;

– the external calls are made on threads using the ThreadPool and the AsyncOperation. So when the work is done on the child thread, the context is switched back to the main UI thread with asyncOperation.PostOperationCompleted() method;

– on the user control, because of this bug, I am using the BeginInvoke method, again to switch context on the main UI thread.

Even using all these techniques to switch back to the UI thread, we are still getting these errors.

The affected workstations must be faulty in some way.

Thank you.