Thank you for your interest in RadTabControl for WPF.
Determining whether to use a single view model or define a separate one for each RadTabItem depends on the exact project needs. I cannot confirm which would be the better approach. However, if you plan to operate with various data source, having a separate view model might be a more reasonable solution. A possible approach for this would be to have a main view model which holds an instance of each separate view model. Then, you should be able to set the DataContext of each RadTabItem to be the needed view model.
Hopefully, this helps.
Telerik by Progress
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