title: Add New Filter functionality in C# projects
body: <p>In <em>C++</em> projects in <em>Visual Studio 2008</em> there is possibility to <strong>Add -> New filter</strong> which will be usefull if one wants to separate some files from others (ie. source files from header files) and keep each type in "semifolders" without moving them physically on the hard disk. I wanted to do the same in <em>c#</em> projects with, lets say xml files, but the only option here is to create folder physically, which I want to avoid. And there are my questions:</p>
  
  <ol>
  <li>Is it possible (and how) to create filters in <em>C#</em> projects?</li>
  <li>Why <em>C#</em> and <em>C++</em> project's <strong>Add</strong> options differ from each other (in first you can add folder(not filter) and in second filter(not folder)?</li>
  </ol>
  
  <p>ps. I am using <em>VS2008</em> and I don't know if this changed in <em>VS2010</em>.</p>