Hide Tags

[Skink]

I'm trying to understand the hide tags. Here's an example:

Reveal Example (Click to Show Hidden Text)

See that gap to the left of this sentence?  Hover over it to see the words 'hereitis' display.
Notice how the next line does not have said gap.

What is that? I looked at the source code, and it isn't an image or anything that will not display for me. Can I get rid of it somehow? Thanks!