Hi,
You won't be able to do it directly because "Insert Table" and "Edit Table" are the same button. So if you click the table button when you are currently inside col1, row1, then it will assume that you want to edit the current table instead of inserting a child table.
There are two ways to do what you wanted to do:
1. Place the cursor somewhere else, then insert a table there. After that you can drag the second table into the first table. This is the easiest way because it does not require any additional code;
2. Implement a custom command or provide a custom dialog to handle the built-in insert table command. The basic idea is you can get the current DOM element in the editor with this function:
http://www.essentialobjects.com/doc/1/jsdoc.public.editor.getcurrentelement.aspxOnce you have the current DOM element (for example, a TD element if you are inside a table cell), you can call DOM interface to modify/add elements to the editor. You may also need a custom dialog for this. See here for more information about how to use custom dialog:
http://www.essentialobjects.com/doc/1/editor/customize_dialog.aspxHope this helps. Please feel free to let us know if you have any more questions.
Thanks!