When longer string is used for HeaderText the text could not be wrapped. Also the issue occurs when using Label with LineBreakMode="WordWrap" inside the TabViewHeaderItem.Content:
Support for interactive TabHeader content (i.e. Buttons, Checkboxes) that does not invoke the tab selection and is aligned next to the tabs
We should consider adding one or more events related to the selection of the TabView control.
Presently the TabView only supports unbound mode and there is no way to bind a list of items from the view model to display as tabviewitems. It would be convenient if there is an ItemsSource property.
Introducing a TabItem.IsTabVisible property would be useful. Currently, if you want to hide a tab, you need to remove it from the TabView.Items collection and cache it in a backing collection. Then, to re-show the tab, remove it from the cache and add it back to the TabItems (preferably at the same index if you've also cached it's position).
At the moment when clicking the overflow button, a list of items is displayed in a Popup. It would be convenient if there is a built-in mechanism for defining a custom action upon clicking the overflow button. For example one might want to open a SideDrawer.