Question

I accidentally pressed some keys in Visual Studio 2010 and ended up with an icon I never saw before placed where the breakpoints are usually placed:

Anyone can tell me what it does and how can I remove it?

Answer 1

Those are bookmarks.

More info here:

http://msdn.microsoft.com/en-us/library/xc3ed5eh.aspx

and here:

http://msmvps.com/blogs/vipul/archive/2006/01/20/Visual-Studio-Bookmarks.aspx

Excerpt from the documentation:

The Bookmarks window is a handy companion tool to the Code Editor. You
can mark lines in your code files with bookmarks and then organize
these bookmarks into virtual folders. This enables you to open files
and navigate directly to the lines marked simply by clicking entries
in the Bookmarks window.

Common procedures for using bookmarks appear below.

In most Visual Studio programming languages, you can also create Task
List shortcuts and comments. As with bookmarks, you can click on any
entry in the Task List to open a file and jump to the line of code
marked. For more information, see How to: Use Task List Shortcuts and
How to: Create Task List Comments.

To create or remove a bookmark using the Bookmarks window

1. Open a source code file for editing in the Code Editor.

2. Place the insertion point on the line of code you want to bookmark.

3. On the View menu, select Bookmark Window.

   The Bookmarks window is displayed. It can be docked along any
   convenient edge of the IDE. The list of bookmark entries includes an
   entry for the newly bookmarked line in the active document.

4. Click the Toggle a bookmark button in the Bookmarks window.

   A bookmark token appears in the Indicator margin of the Code Editor
   next to the selected line. Click the button again to remove the
   bookmark.