TraceListener does not output all traces

Question

I've configured my WPF application with the following TraceListener

<system.diagnostics>
  <trace autoflush="true" indentsize="4">
    <listeners>
      <add name="myListener" type="MyApp.RollTraceListener, MyApp" initializeData="myapplication.log" />
      <add name="listener" type="System.Diagnostics.TextWriterTraceListener" initializeData="application.log" />
    </listeners>
  </trace>
</system.diagnostics>

In Release, the TRACE constant is defined but I have not the same content in both files. What am I missing ?

public class RollTraceListener : System.Diagnostics.TraceListener
{
   string fileName;
   DateTime startDate;
   StreamWriter traceWriter; 

   public RollTraceListener(string fileName)
   {
      this.fileName = fileName;
      this.startDate = System.DateTime.Now;
      var stream = new FileStream(this.fileName, FileMode.Create);
      traceWriter = new StreamWriter(stream);
   }

   public override void Write(string value)
   {
      traceWriter.Write(value);
   }

   public override void WriteLine(string value)
   {
      traceWriter.WriteLine(value);
   }

   protected override void Dispose(bool disposing)
   {
      if(disposing)
      {
         traceWriter.Flush();
         traceWriter.Close();
      }
   }
}

Typically, if I just write System.Diagnostics.Trace.WriteLine("Hello World!"); the line is present in application.log but not in myapplication.log