We had an issue recently with styling tables in EPiServer.  EPiServer implements the tinyMCE project as the text editor within Epi. tinyMCE is very flexible and uses a plug-in based framework to allow customization like adding custom buttons and overriding default behaviour.  

In Episerver, if an editor wants to add a table to a page, they can click  on the table button which launches a model that allows them to add columns, add a style.  Our problem is our site uses a custom table style and we did not want editors to manually have to modify any HTML directly.

To get around the problem I wanted to pre-populate the style box with a list of our custom styles.  I thought finding information about adding in a style would be simple, but after a few hours of searching, I couldn't find a tutorial on how to do it in EPi. I found two approaches to solving this problem so I thought I would share them 1) If you open the table.html file you can manually add in the styles in the HTML mark-up of the form.

If you go to:

C:\Program Files (x86)\EPiServer\CMS\6.1.379.0\Application\Util\Editor\tinymce\jscripts\tiny_mce\plugins\table\table.htm

You should be able to see the following snippet, simply add a new option for each new style you require.

{#class_name} tablestyle01   

Now if you open up Episerver you will see all the styles added into the table dialogue

epserveritinymcetable