The ContextSwitchDeadlock doesn't necessarily mean that the code has an issue, just that there is a potential. If you go to Debug > Exceptions in the menu and expand the Managed Debugging Assistants, you will find ContextSwitchDeadlock is enabled. If you disable this, Visual Studio will no longer warn you when items are taking a long time to process.
The cases of a large export of many UI elements can be considered a long-running operation, thus probably the cause of the deadlock. However, that does not mean that operation will not pass after some time and that the export will fail.
You can find more information about it here: https://msdn.microsoft.com/en-us/library/ms172233(v=vs.110).aspx
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