title: Devexpress textbox regular expression validator not validating correctly
body: <p>For some reasons, I have to use devexpress textbox instead of asp textbox, and the textbox have a validation that the text must contain a ".", so I am using regular expression to validate the user's input like below:</p>
  
  <pre><code>&lt;dx:ASPxTextBox runat="server" ID="textBox1"  ValidationSettings-ValidationGroup='&lt;%# Container.ValidationGroup %&gt;'&gt;
                                                              &lt;ValidationSettings&gt;
                                                                  &lt;RegularExpression ValidationExpression="[.]" ErrorText="Invalid input" /&gt;
                                                              &lt;/ValidationSettings&gt;
                                                          &lt;/dx:ASPxTextBox&gt;
  </code></pre>
  
  <p>I.e. the regex is very simple, just <code>[.]</code></p>
  
  <p>I tested the regex on this site <code>http://regexpal.com/</code> and it's validating properly, but when it's put inside the aspxTextbox, whenever the user type in anything that contains ".", the validation isn't passed (i.e. error text shows), why this happens?</p>