Measuring sessions for Sitecore 6 sites

I recently had to do some performance and stress tests on a Sitecore 6 website. But no matter what I did, the Perfmon showed 0 sessions.
At first I blamed the built in session handling in Sitecore, where Sitecore persists the Shell users. But the solution was elsewhere.

In order to measure sessions you must add the Session_Start and Session_End functions to the global.asax:

<%@ Import namespace="Sitecore"%>
<%@ Import namespace="Sitecore.Diagnostics"%>
<%@ Application Language='C#'%>
<script runat="server">
  public void Application_Start() { }
  public void Application_End() { }
  public void Application_Error(object sender, EventArgs args) { }
  public void Session_Start(Object sender, EventArgs e) { } // Add this to your global.asax
  public void Session_End(Object Sender, EventArgs e) { }   // Add this to your global.asax
</script>

There is no need to fill anything into the functions. They just have to be there. After this I could measure the sessions with Perfmon.

UPDATE: This is actually not a Sitecore 6 issue but a general .NET issue. It is not even a bug but expected behaviour. .NET will not instantiate the session object if no one uses it. This is a pretty clever way of saving memory.
When adding the Session_Start() and Session_End() events in the global.asax, the auto event wireup will automatically force an instantiation of the session object, making the .NET process store session data.

Firefox only prints first page of contents

It seems that there is a bug loose from the dawn of Firefox that disables printing of other pages but the first one on certain websites. Several solutions have been suggested, but none of them worked for me.

Then I approached the problem rationally. I simply disabled all style sheets, then added the style elements one by one until the print failed. I found the problem in the folllwing .CSS code:

.ThreeColumn .ContentBlock
{
    float: left;
    width: 440px;
    padding: 10px 20px 20px 20px;
    background-color: #FFFFFF;
    overflow: hidden; /* here is my problem! */
}

The problem is the overflow:hidden. When this attribute is set, Firefox only prints the first page. Maybe Firefox interprets the overflow:hidden as a command to hide text when overflowing to another page in the print?

Anyway, I removed this attribute and my page printed nicely.