Add a footer in the ComboBox dropdown

[Fritierkelle]

Could you add a footer for an item like "Edit" or "Add New" that is below the scrollable part?

Example from the internet:

I don't think it's possible for someone like me to realize something like this with a template, also because of the time involved.

(I thought, just put a margin bottom under the scrollviewer in the default template and put a button, but it needs a new control to add the button to the border, which destroys the whole behavior. :) )