As to first question - I don't understand where you want to display this two horizontal lines. Please send to us screen shot whit your design of RadTabcontol.
As to second question - In the new version (Q1) we use ContentPresenter. Unfortunately, it is not possible to change the foreground of the TabItem because of the ContentPresenter that the Tab uses internally. The ContentPresenter itself does not expose a Foreground property.
Please find attached a project with a workaround. In the project I made a custom theme of TabItem control and replaced the ContentPresenter with ContentControl. Using this change means that you will not be able to change the theme at Runtime.
All the best,
the Telerik team
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