Okay, let me just say, this isn't super important, but I've really been wondering lately.

The docked tabs in Visual Studio 2012 Express (On the sidebar) have seemingly random red dots/lines to the left of the text. Sometimes they are there and sometimes they aren't.

**EDIT:** A friend of mine said he also has them, however they are green, but that is probably because he uses a different color theme.

Here is an example:

![Weird Lines](https://i.stack.imgur.com/3u9ZJ.png)

Closer:

![o3o](https://i.stack.imgur.com/pHAEw.png)

I docked a ton of tabs on purpose, normally I only have 2 over there.

I also noticed a few of them had no lines, but when I moused over them they appeared.

So, Is this a bug? Is this a subtle feature? I have no clue, could this just be something on my computer?