Scrolling bar's path visible although there is no scrolling need...

I set my frame like this:

<frameset cols="550,200" frameborder="NO" border="0" framespacing="0"> 
  <frame name="mainFrame" src="leftframe.htm" scrolling="yes">
  <frame name="rightFrame" src="rightframe.htm" scrolling="no">
</frameset>

And, when I preview it in my browser I see a unused, unfunctioning, dimmed scrollbar on the right. Like the one you see the one on the right (If you are using Outlook Express 5.0). Is there any way to disable it. I am sure there is, and I've seen some sites like that but Is there anything tricky I should know. Thanks in advance for your help.