Hi,
We have looked into this issue and apparently it is more complicated than we though. We have no problem re-routing WM_TOUCH through application. However the problem is the parameter of the WM_TOUCH message is a "touch handle" that is only valid in the original process --- in this case is the browser engine process, as such you will not be able to get additional touch information inside your process. This makes rerouting this message through your process useless.
To achieve your goal, you can consider using WebView.JSInitCode to inject some JavaScript into the web page that monitors the touch event. All touch event information will be available to your JavaScript code since this is entirely inside the browser engine. You can then perform whatever logic there. If you need to communicate to your application, you can use JavaScript extension to do so:
https://www.essentialobjects.com/doc/webbrowser/advanced/jsext.aspxThanks!