Use IRichEditOleCallback for wxTextCtrl's context menu.

In wxMSW, use IRichEditOleCallback::GetContextMenu() to provide our
default context menu for rich text controls, instead of using
EVT_CONTEXT_MENU.

The latter completely overrides native control's handling and in
particular breaks Windows 8's builtin spellchecking support.

Fall back to the previous non-OLE code for older richtext versions.

Also make the new MSWCreateContextMenu() method virtual so that the
context menu can be customized.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76723 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/window.cpp

@@ -2335,6 +2335,8 @@ bool wxWindowMSW::HandleMenuPopup(wxEventType evtType, WXHMENU hMenu)
     {
         menu = wxCurrentPopupMenu;
         isPopup = true;
+        if ( evtType == wxEVT_MENU_CLOSE )
+            wxCurrentPopupMenu = NULL;
     }
     else
     {