Thank you for contacting us.
Actually this is a known issue that is reproducible in VisualStudio 2010 and we have already logged it into our bug tracking system. I am afraid that at this point I cannot give you any time-frame when this problem could be resolved.
As a workaround I would suggest you to drag and drop the control in the designer instead of double clicking.
I hope this information is helpful for you. Don't hesitate to contact us again if you have further questions.
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