Handle WM_*MENU* events in wxWindow.

Contrary to MSDN implications, at least some of these messages are not
actually sent to the TLW for popup menus, but to the owning window or
even its parent window (!).

Move the handling of these events from wxTLW to wxWindow.  Move menu
depth tracking to wxFrame, because it only makes sense for frame's
menus and move DoGiveHelp() from wxTLW to wxFrame.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76721 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/frame.h

@@ -104,6 +104,9 @@ public:
     // normal frames but is overridden by wxMDIParentFrame
     virtual WXHMENU MSWGetActiveMenu() const { return m_hMenu; }
 
+    virtual bool HandleMenuSelect(WXWORD nItem, WXWORD nFlags, WXHMENU hMenu);
+    virtual bool DoSendMenuOpenCloseEvent(wxEventType evtType, wxMenu* menu, bool popup);
+
     // Look up the menu in the menu bar.
     virtual wxMenu* MSWFindMenuFromHMENU(WXHMENU hMenu);
 #endif // wxUSE_MENUS
@@ -150,6 +153,10 @@ protected:
 #if wxUSE_MENUS
     // frame menu, NULL if none
     WXHMENU m_hMenu;
+
+    // The number of currently opened menus: 0 initially, 1 when a top level
+    // menu is opened, 2 when its submenu is opened and so on.
+    int m_menuDepth;
 #endif // wxUSE_MENUS
 
 private: