I tried to make a simple VST with a WPF gui, all from scratch, without using VST.NET and I'm stuck on a horrible keyboard issue (in cubase): the keyboard is not properly redirected to the WPF window. I found this: http://blogs.techsmith.com/inside-techsmith/keyboard-input-in-mfcwpf-inter/#.UFS29FHWr3U
the trick is to respond to DLGC_WANTALLKEYS to WM_GETDLGCODE
and null out HACCEL.
Actually, I tried only the first step (WM_GETDLGCODE) and my gui receive the keyboard BUT all cubase shortcut grab the keyboard before my GUI. I will try the HACCEL stuff ... when I'll understand it :-)
your WpfControlWrapper use HwndSourceParameters like I expected, but what about keyboard ? Does theses stuff are used in VST.NET ?