How to reproduce:
1. Add a new RadTabbedForm to a VS2017 VB.NET project.
2. Select the new form in the design view window
3. In the properties box, got to "Tabs" and click the ellipsis (…)
4. The collection editor opens.
5. Click the first tab in the list and change the "Text" property to something new
6. Click "OK" to save changes