Display an Adorner over a WebBrowser control

I don't think that will work with an Adroner, but you can float content over a WebBroswer control using a transparent Popup control. More details and a code sample can be found here.

Here's my blog post introducing a library I wrote for layering a WPF adorner over any hwnd. A simple web browser demo looks like this:

This is caused by airspace issues. Since a WebBrowser is a native, non-WPF control, there is no way to directly render adorners (or other WPF content) on top of it.

In order to do this, you need to use a separate window of some sort, and put the content into that separate window. This typically means using a transparent WPF window layered over the top of your main window. Unfortunately, this will not be as integrated of a solution as a true native WPF control would provide.