title: How do you prevent Visual Studio 2012 from automatically closing preview files?
body: <p>Visual Studio 2012 appears to have a new feature that distinguishes between files that have been explicitly opened for editing and files that have been navigated to (these "preview" files default to the right side of the file tabs on the top of the environment and have a default tab color of purple).</p>
  
  <p>While it is possible to keep a preview file open by clicking on the "Keep Open" button in the tab, I find myself looking for files that I expect to be open, but have been closed by Visual Studio without my direct input.</p>
  
  <p>Is there a setting available that automatically converts preview files to open files (i.e. just skips the preview mode entirely)?</p>