When the RadPane that contains the RadMap is redocked to another location then the RadMap locks the browser.
The RadMap loses its data context and gets null into Provider property. When the data context is restored and the RadMap gets its provider then it hangs, because all calculations inside its logic require map provider which contains necessary information about current projection.It is no problem to change map provider from one to another, but the problem occurs when the map provider is changed to null. 
At least the RadMap should raise exception in a case when the Provider property is assigned to null.