how to remove the border between the window title and content

Question

I have create a Window with Ribbons (2010 - Microsoft.Windows.Controls.Ribbon).

It looks like that:

Now, is there a border over the tabs (between the tabs and the title). This is very ugly.

It should looks like Microsoft Office Word:

What can I do, that there is no border between the tabs and the titlebar?

(The RibbonWindow is used)

Answer 1

It looks like you're using the standard WPF Window. Try using the Ribbon framework's RibbonWindow instead. It integrates the Ribbon into the window itself rather than just containing it like a normal control, which is what Window does.

Answer 2

I use now the Fluent Ribbon, that solve the problem.