Transparent window to trap mouse clicks

I have a need to display a web page to a user through a webbrowser component, but on occasions I need to fix it so that mouse clicks do NOT go through to the web page, but are trapped and the pixel coordinates sent back to my app. I therefore need a minimal example app consisting simply of a web browser and a menu bar. When the user selects "Report" from a "Tools" menu any clicks made make a messagebox appear with the pixel coordinates of the webbrowser.? When the user selects "Normal" from the "Tools" menu the clicks will follow any hyperlinks on the webpage in the usual manner. Bidders might like to note that I tried the approach of putting a transparent panel over the webbrowser, but then the underlying window wasn't refreshed so you kepp on seeing the drop-down tools menu. Perhaps some clever means of routing windows messages would work, or perhaps it needs a completely different approach.