Unfortunately, I must confirm that an exception is thrown in the described set up.
The reason for this is that internally the RadCloudUpload uses ClouduploadFile objects (as upload workers). The CloudUploadFile exposes a few commands, like the StartUploadCommand. When a command changes its CanExecute state, we invoke the CanExecuteChanged handler of the worker. The change of the CanExecute state may very well happen in a background thread, but the CanExecuteChanged invocation needs to happen on the UI thread. This is why we now use the Application.Current.Dispatcher to dispatch the invocation. In win forms, there is no Application.Current, hence the exception.
We understand that this is pretty inconvenient and we will investigate the possibilities of removing this limitation. Unfortunately, we cannot offer a work-around at this moment, we hope that you can wait for the next SP (out in early December). I have updated your Telerik points as a thank you for letting us know of this issue.
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