Adding symbols panel to the customized work space

I have been working on customizing my Work space, adding both user defined brushes, swatches and patterns. All is working perfectly, except from when I try to add user defined symbols to my work space. 

Once added in the same column as user defined brushes & swatches, I will save both the Work space and the document.

But once I open a new document, only brushes and swatches will remain - I then manually have to find user defined symbols. (The standard Symbols window has no problem and will still be there when i save my Work space and open a new document)

I hope someone can help med find a solution for this!

Thanks