I want to remove the shopping cart sidebox from the account history page.

I have looked at other threads and in particular this one: http://www.zen-cart.com/forum/showthread.php?t=63813

So following that pattern I wanted to add something like this:

PHP Code:
 if ($_GET['main_page'] == 'account_history_info'){
$show_shopping_cart_box = false;
} 
However that did not produce any results as the shopping cart side box still appears. Nor did it do anything if I changed to 'account_history' instead of 'account_history_info' nor if I used both statements.

Interestingly, however, if I do the following:

PHP Code:
if ($_GET['main_page'] == 'account'){
$show_shopping_cart_box = false;
} 
then the shopping cart sidebox disappears when going to the "My Account" link...however, it reappears when I then move to the account history pages...

Any suggestions would be appreciated. Thanks, Ken

Forgot to mention that the file I am talking about modifying is: shopping_cart.php