Visual Studio 2012 generate Locale Resource for ascx that itself cannot open

We have our own controls that does not assign caption/text at design but assigned at runtime. But we have some other controls have caption specified on design so we still want to generate locale resource. When using Generate Locale Resource on the ascx file, it creates resx with the attribute type="System.Resources.ResXNullRef, System.Windows.Forms":

  <data name="composerTitle.Text" type="System.Resources.ResXNullRef, System.Windows.Forms">
    <value />

But VS 2012 cannot open this resx file. It got error "The operation could not be completed. Invalid pointer".  VS 2010 have no trouble to open these resx. If I remove thees attributes in resx file, then VS 2012 can open it. But since we have controls have no text assigned at design/markup, this will happen again next time.

I think this is a bug in VS 2012, it can create resx with this attribute but itself cannot open it, while this is OK in VS 2010?