Underscores need to appear in code sections of a post

For some reason the underscore appears in some posts but not others. I’m not sure why.

In this post, underscore appears on some places but not others.
http://forums.electricimp.com/discussion/807/sending-an-array-via-output-port-and-then-http-request#Item_5

Below, the script has an underscore between $ and POST … showing here as a space.
When I edit this post, I see the underscore as it exists.
But the next place, print_r shows the underscore OK … why is this?

`

<?php $items=$_POST['value']; echo "This is the array of values:
"; print_r($items); echo "

These are the items individually:
"; echo $items[0]."
"; echo $items[1]."
"; echo $items[2]."
"; ?>

`

I’m figuring it out that the underscore won’t appear after the $ character.

.

Looks like a problem with the stylesheet, or perhaps with Firefox (if you too are using Firefox, that is). The underscore is there (you can copy-and-paste it) but it’s getting overprinted by the following line. The one in the print_r line has a blank line following, so doesn’t get overprinted.

Peter

I use FF on one, Chrome on another, and also view sometimes with a Kindle. Missing the underscore on all of them (only on the line with the $_POST).