While upgrading http://social.clipflair.net to MonoX v4.9.40.4845 [12/25/2013], DB v4.7.3842 I see in the logs:

2014-06-02 18:20:16,255 [125] ERROR MonoX [BaseHttpApplication] - Application Error
</br>System.Web.HttpParseException (0x80004005): The base class includes the field 'ctlMenu', but its type (MonoSoftware.MonoX.ModuleGallery.MonoXMenuHTML5) is not compatible with the type of control (ASP.monox_modulegallery_monoxmenusimple_ascx). ---> System.Web.HttpParseException (0x80004005): The base class includes the field 'ctlMenu', but its type (MonoSoftware.MonoX.ModuleGallery.MonoXMenuHTML5) is not compatible with the type of control (ASP.monox_modulegallery_monoxmenusimple_ascx).
</br>   at System.Web.Compilation.BaseTemplateCodeDomTreeGenerator.BuildFieldDeclaration(ControlBuilder builder)
</br>   at System.Web.Compilation.BaseTemplateCodeDomTreeGenerator.BuildSourceDataTreeFromBuilder(ControlBuilder builder, Boolean fInTemplate, Boolean topLevelControlInTemplate, PropertyEntry pse)
</br>   at System.Web.Compilation.BaseTemplateCodeDomTreeGenerator.BuildSourceDataTreeFromBuilder(ControlBuilder builder, Boolean fInTemplate, Boolean topLevelControlInTemplate, PropertyEntry pse)
</br>   at System.Web.Compilation.BaseTemplateCodeDomTreeGenerator.BuildSourceDataTreeFromBuilder(ControlBuilder builder, Boolean fInTemplate, Boolean topLevelControlInTemplate, PropertyEntry pse)
</br>   at System.Web.Compilation.MasterPageCodeDomTreeGenerator.BuildMiscClassMembers()
</br>   at System.Web.Compilation.BaseCodeDomTreeGenerator.BuildSourceDataTree()
</br>   at System.Web.Compilation.BaseCodeDomTreeGenerator.GetCodeDomTree(CodeDomProvider codeDomProvider, StringResourceBuilder stringResourceBuilder, VirtualPath virtualPath)
</br>   at System.Web.Compilation.BaseTemplateBuildProvider.GenerateCode(AssemblyBuilder assemblyBuilder)
</br>   at System.Web.Compilation.AssemblyBuilder.AddBuildProvider(BuildProvider buildProvider)
</br>   at System.Web.UI.TemplateParser.ProcessException(Exception ex)
</br>   at System.Web.UI.TemplateParser.ParseStringInternal(String text, Encoding fileEncoding)
</br>   at System.Web.UI.TemplateParser.ParseString(String text, VirtualPath virtualPath, Encoding fileEncoding)
</br>   at System.Web.UI.TemplateParser.ParseFile(String physicalPath, VirtualPath virtualPath)
</br>   at System.Web.UI.TemplateParser.Parse()
</br>   at System.Web.Compilation.BaseTemplateBuildProvider.get_CodeCompilerType()
</br>   at System.Web.Compilation.BuildProvider.GetCompilerTypeFromBuildProvider(BuildProvider buildProvider)
</br>   at System.Web.Compilation.BuildProvidersCompiler.ProcessBuildProviders()
</br>   at System.Web.Compilation.BuildProvidersCompiler.PerformBuild()
</br>   at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath)
</br>   at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
</br>   at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
</br>   at System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean throwIfNotFound)
</br>   at System.Web.Compilation.BuildManager.CreateInstanceFromVirtualPath(VirtualPath virtualPath, Type requiredBaseType, HttpContext context, Boolean allowCrossApp)
</br>   at System.Web.UI.PageHandlerFactory.GetHandlerHelper(HttpContext context, String requestType, VirtualPath virtualPath, String physicalPath)
</br>   at System.Web.HttpApplication.MaterializeHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
</br>   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

this is logged for every page access, but the menu does seem to work

note that I'm using a 4.x AjaxControlToolkit, having in web.config the following:

  <runtime>
</br>    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
</br>      <dependentAssembly>
</br>        <assemblyIdentity name="AjaxControlToolkit" publicKeyToken="28f01b0e84b6d53e" culture="neutral" />
</br>        <bindingRedirect oldVersion="0.0.0.0-3.0.30930.28736" newVersion="4.1.60623.0" />
</br>      </dependentAssembly>
</br>    </assemblyBinding>
</br>  </runtime>

but I don't think that one is the issue

</br>