(QEmu 0.9.1)
livecd-73189-dbg.iso

*****

Case 1 (Keyboard, right arrow)
and
Case 2 (Mouse, hover)
{{
(dll/win32/userenv/profile.c:891) Error: 2
shellpath.c:1459: _SHGetUserProfileDirectoryW returning
CStartMenu.cpp:193: Unexpected failure 80004005.
CMenuToolbars.cpp:1262: Unexpected failure 80004005.
}}

Case 3 (Mouse, left click)
{{
(dll/win32/userenv/profile.c:891) Error: 2
shellpath.c:1459: _SHGetUserProfileDirectoryW returning
CStartMenu.cpp:193: Unexpected failure 80004005.
CMenuToolbars.cpp:1262: Unexpected failure 80004005.
traywnd.cpp:2804: Unexpected failure 80004005.
}}
And "Start" menu closes :-/

*****

reactos/dll/win32/shell32/shellmenu/CStartMenu.cpp
 152     HRESULT OnGetSubMenu(LPSMDATA psmd, REFIID iid, void ** pv)
...
 192                 hr = SHGetFolderLocation(NULL, csidl, 0, 0, &pidlStartMenu);
 193                 if (FAILED_UNEXPECTEDLY(hr))

reactos/dll/win32/shell32/shellmenu/CMenuToolbars.cpp
1248 HRESULT CMenuStaticToolbar::InternalPopupItem(INT iItem, INT index, DWORD_PTR dwData, BOOL keyInitiated)
...
1261         HRESULT hr = m_menuBand->_CallCBWithItemId(iItem, SMC_GETOBJECT, reinterpret_cast<WPARAM>(&IID_IShellMenu), reinterpret_cast<LPARAM>(&shellMenu));
1262         if (FAILED_UNEXPECTEDLY(hr))

reactos/base/shell/explorer/traywnd.cpp
2794     LRESULT OnCommand(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
...
2804         if (m_TrayBandSite == NULL || FAILED_UNEXPECTEDLY(m_TrayBandSite->ProcessMessage(m_hWnd, uMsg, wParam, lParam, &Ret)))