How can I get both the game and the WebBrowser to capture the cursor?

I’m using the WebBrowser as an overlay of the whole user’s viewport to display HTML content.
Most of the background is transparent so that the user can see the game through.

The problem is because the WebBrowser fills the whole viewport I cannot get the game to capture my mouse and respond to mouse events.
How can I do to get both the WebBrowser widget element and the game to respond to the cursor?

Thank you

I have same issue