There might be some differences when you define the ToolTip inline and when you define it with extended markup syntax
especially with how the DataContext is transferred because the tooltip uses Popup and Popups are usually in separate visual tree. However, I believe it is possible to workaround such limitations either with manual setting of DataContext or with a Converter. As for the ProgressBar , you can replace it with System.Windows.Controls.Button to check if the problem is not in Telerik Controls. On the other hand, for the binding issues you can refer to some stackoverflow posts.
You can also send us an isolated sample in a separate support thread. This way we would be better able to investigate your scenario and advice you better.
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.