Windows Phone 8 Designer not painting properly

I experienced a painting problem  while working with windows phone 8 projects. Problem is, 

Ex:

When inserting a Text box to the form, that text box not showing properly at the designer or some time it is not  showing at the Designer. If we needs to see it, have to re size the area of the designer or need to Zoom in or out the designer. Then painting method works and show the inserted components in the designer. 

Try so-many things and finally found it's coming from my VGA card. I am using a Dell Inspiron 15 and its having a RADEON dedicated VGA card and once i disable it, now it is working.

To whom i have to make the Blame. 

RADEON or VS2012?