Peter,
Based on my research, it seems that Managed Webrowser did not expose such
interface.
Right, I would have expected it also to be in the webbrowser direct.
See my reply on the repeated question from the OP where is the way to get it
editable.
I got with that the webbrowser again editable, howeve a really looking buggy
way (I will not say it are bugs, however no documentation as well of course)
and therefore a lot of work.
Just a start of course, because working with MSHTML and the Webbrowser
seems easy, however most time a lot of pain if it becomes to question like
the OP is now asking.
Cor