title: How to filter by what the user enters in a textbox, except show all if it's empty
body: <p>I want to filter a form with a query, so that the user has to input what he would like to search in a textbox and it gets filtered out. There are some empty fields, and these should show if the user has not searched for anything yet, but if he searches those should not be shown anymore.</p>
  
  <p>With this code, the searching works, but it shows the empty fields:</p>
  
  <pre><code>Like("*" &amp; [Forms].[BerichtSuche].[efTitle] &amp; "*") OR Is Null 
  </code></pre>
  
  <p>I tried this, but then nothing at all is shown:</p>
  
  <pre><code>If(Len([Forms].[BerichtSuche].[efTitle].[Text])=0; 
    Like("*" &amp; [Forms].[BerichtSuche].[efTitle] &amp; "*") OR Is Null; 
    Like("*" &amp; [Forms].[BerichtSuche].[efTitle] &amp; "*"))
  </code></pre>