In my VC++ application I have an embedded browser (MSHTML). It works fine and handles the mouse properly (for instance, clicks and selects are processed OK). However, mouse wheel rotations over the embedded browser do not have any effect. This is my problem.
I am not very familiar with the internals of MSHTML embedding, and OLE in general. This is an wxWidgets application (wxWidgets is a C++ GUI library), and I am making use of its IEHTMLWin component (which hosts an MSHTML control and wraps it in the wxWindow interface). However, I do have the source and am willing to do some debugging.
Forgetting wxWidgets and speaking purely about OLE and MSHTML, what’s the right place to start looking for the problem cause? I tried naive googling for variants of ‘mshtml mouse events’ or ‘mshtml wheel’, but didn’t give any good pointers.
Should you want to take a look at the code of IEHTMLWin, it can be browsed here. The iehtmlwin.c file (1,5 k lines) has all the OLE-related code and implements all interfaces needed to host a web browser control. It’s worth noting that mouse events don’t proceed to the containing wxWindow at all (OnMouse is never called).
{UPD} mshtml version: 6.00.2900.3314. Other applications that host this control (including IE) support the wheel. {/UPD}
jdigital hint (regarding winspector) was very helpful. After some message sniffing, I realize that the problem is focus-related. A click on the browser control somehow does not set focus on the browser control (unlike, say, RichEdit), and WM_MOUSEWHEEL is not sent there. So the new problem is setting the focus.
Try Winspector (http://www.windows-spy.com/) which will allow you to see the windows messages. Make sure that the scroll wheel events are getting passed through.