Hi Michael,
I tried this myself quite some time ago, and found that it cannot be done. The problem here is that the code editor, directly invokes the IOleCommandTarget on the language service. The QS and Exec are immediately processed, and there are no hooks in between that'll allow you to change up the behavior.
The other problem is that when you call IVsTextView::AddCommandFilter, you have no control over where in the filter chain it gets placed. So some other IOleCommandTarget may process the command, and you'll never see it.
One suggestion that comes to mind is to see if you can hook the ECMD_SHOWCONTEXTMENU command from a
priority command target . I haven't tried this, but if you could intercept that command, then you could display your own context menu instead of the stock IDM_VS_CTXT_CODEWIN context menu.
Sincerely,
Ed Dore