It is always only display the first submenu ...
windows 7 64bit
C::B svn 10320 x64 with wxWidgets 2.8.12
TDM-GCC-64
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class TestPlugin extends cbScriptPlugin {
    // mandatory to setup the plugin's info
    constructor() {
        info.name = _T("EasilyGCC");
        info.title = _T("Target Setup");
        info.version = _T("0.1a");
        info.license = _T("GPL");
    }
    // optional to create menubar items
    function GetMenu() {
        local entries = ::wxArrayString();
        entries.Add(_T("Project/EasilyGCC/EasilyGCC0"), 1);
        entries.Add(_T("Project/EasilyGCC/EasilyGCC1/Arch1"), 1);
        entries.Add(_T("Project/EasilyGCC/EasilyGCC1/Arch2"), 1);
        entries.Add(_T("Project/EasilyGCC/EasilyGCC1/Arch3"), 1);
        entries.Add(_T("Project/EasilyGCC/EasilyGCC2"), 1);
        entries.Add(_T("Project/EasilyGCC/EasilyGCC3"), 1);
        return entries;
    }
}
RegisterPlugin(TestPlugin());