Using cornerstone I can add a feature list within a column and I can add tabbed content but I don’t seemed to be able to add a feature list within tabbed content. I need to be able to have icons and lines linking the list.
Hi there,
There is no Shortcode listing for the Feature List so that you can not add it normally to the tab. I suggest that you add a new page and in Cornerstone only add a Feature List and set it as you like. Then save it, Go to that page edit screen and click on Visual Or Text option to go out of the Cornerstone. You will be prompted but click Process Anyway:

After that select the Feature List section from the code:

Then paste it into the content section of the Tab Element:

Then you will have the Feature List inside the Tab:

Please make sure that you keep the Page which you have created as if you want to edit the Feature List you need to do all the stuff all over again.
Thank you.
That worked perfectly! Thank you and thanks for your quick response 
You’re very welcome
Glad that we could be of a help.