There was a thread asking how do do this. I found out how to do it today. If you are using quote tracker, go to options, then charts. Change the color of last price to white and there you go. No visible shadows. Worked great for me today.
That's all well and good if the background color of your chart happens to be white and you don't care if you can't see the displayed price. It sure would be a lot nicer if a fix was developed that allowed the user to hide the shadows as an option, but still allowed the last price to be displayed.
Show bid/ask and you have all the prices you need. Many times the bid/ask aren't nearly as high or low as the lenght of the shadow. For example, as in the case of a spike.