Sitefinity ASP.NET CMS is a web-based content management platform and Telerik's RadEditor plays a key role in managing the web site's content. RadEditor is a WYSIWYG web-based editor that makes it easy to create rich-text content.
In a nutshell, RadEditor empowers editors to create HTML without knowing HTML.
RadEditor is part of the Telerik's RadControls for AJAX UI suite. Sitefinity comes included with this entire suite of UI products. All of these controls are available to use within your Sitefinity project.
Tools, Tools and more Tools
RadEditor alone is a very powerful product and has many tools available. Out of the box, only a fraction of these tools are enabled in Sitefinity. There are over 60 tools that can be easily added to RadEditor (full list of RadEditor tools).
In fact, if all the tools are enabled, it becomes overwhelming....

Enabling ALL tools might be unpractical, however you might discover a handful of tools that would be very useful for your web site.
Adding New Tools to RadEditor in Sitefinity
There is an XML configuration file that controls what tools are available in RadEditor and how these tools are visually displayed. For Sitefinity's, this RadEditor configuration file can be found at:
~/Sitefinity/Admin/ControlTemplates/EditorToolsFile.xml
In this XML file you'll see several <tools> sections that look like this:
<tools dockable="false">
<tool name="Bold" shortcut="CTRL+B"/>
<tool name="Italic" shortcut="CTRL+I"/>
<tool name="JustifyLeft" />
<tool name="JustifyCenter" />
<tool name="JustifyRight" />
<tool name="JustifyFull" />
<tool name="InsertOrderedList" />
<tool name="InsertUnorderedList" />
<tool separator="true"/>
</tools>
Adding a new tool simply requires a new <tool> element. This <tool> element can be added to an existing <tools> section or you can create a new <tools> section. The <tool> name will need to match the name of an existing RadEditor tool.
The organization of the <tools> and <tool> elements can be changed however you wish. The ordering and grouping of these elements will control how these tools are visually displayed.
Below is a <tools> section that enables font size, font color and background color to be set:
<tools dockable="false">
<tool name="FontSize" />
<tool name="ForeColor" />
<tool name="BackColor" />
<tool separator="true"/>
</tools>
This will add 3 new tools to RadEditor:
Incoming Rant!!!! Just for the record, I think allowing editors to arbitrarily use whatever font, font size, font color and background color they want is a bad idea. Not only does this generate a lot of extra HTML (embedded styles), but you'll lose presentation consistency on your web site. In addition, it's impossible to re-design your web site later if its littered with embedded font styles.
Instead, I'm a much bigger fan of pre-defined styles that editors can select from. Many big companies have usage guidelines for logos & various marketing material. These guidelines specify the font, the spacing and contain strict usage rules. This might seem overly bureaucratic, but strong brand recognition doesn't come naturally. I recommend that you work with the marketing department to create guidelines and then enforce these guidelines through Sitefinity & RadEditor. (More about this in later blog posts.)
This being said, in past jobs I was forced to let go of this due to popular demand. Then, one day, I would load the web site and think "Oh great, there is now a dancing cowboy GIF on main page...yeah that's really cute. I'm sure this will be the thing that convinces our online customers to make a purchase." *sigh*
Bitter? Me? Nah... :)