title: Using "\b" in a .NET regex
body: <p>Can someone explain me why results 1,2 and 3 are false? Looks like a trivial problem.. but still, I'm stuck :/</p>
  
  <pre><code>        string input = "foo abc defg bar";
          string pattern = "abc defg";
  
          string pattern1 = "\b" + Regex.Escape(pattern) + "\b";
          string pattern2 = "\b" + pattern + "\b";
          string pattern3 = "\babc defg\b";
          string pattern4 = pattern;
  
  
          bool result1 = Regex.IsMatch(input, pattern1); // FALSE
          bool result2 = Regex.IsMatch(input, pattern2); // FALSE
          bool result3 = Regex.IsMatch(input, pattern3); // FALSE
          bool result4 = Regex.IsMatch(input, pattern4); // TRUE
  </code></pre>