title: Visual Studio IDE Feature: Filters; What is the Filter property used for?
body: <p>When you are in a solution and have the "Show All Files" button disabled in the Solution Explorer.  You see a logical (filtered) view with some sort of "virtual" folders called filters.</p>
  
  <p>You can add new filters (Right Click Project -> Add -> New Filter).  You can add new files under a filter, or drag and drop existing files into an existing filter (they behave much as if they were actual folders).</p>
  
  <p>On the properties page of a filter there's a few properties.  Some are self-explanatory:</p>
  
  <ul>
  <li>Parse Files: True/False: Files in this filter are parsed for
  autocomplete and other designers</li>
  <li>SCC Files: True/False: Files in this filter are available to version control systems.</li>
  </ul>
  
  <p>What I can't understand is the:</p>
  
  <ul>
  <li>Filter: Text input: Specifies a filter.</li>
  </ul>
  
  <p>For example, a default C++ app might have a Source Files filter with a Filter property of: <code>cpp;c;cc;cxx;def;odl;idl;hpj;bat;asm;asmx</code>.  However, it doesn't really matter what I change here, I could blank it out, or replace it with something like <code>txt</code> I don't see any differences.  I'm not sure how this is even used by Visual Studio, and I could not find any references on its use.</p>