When creating a symbol you can have multiple sections. In the Section field of the edit symbol panel, you can Add New, Add Exisiting or Remove. A symbol can have multiple Sections. If you Select Add New it will Add a New Letter to the symbol in the drop down menu(see buttons on screen shot below). Add new will give you a new edit screen attached to a new Letter which will reflect a new section of the symbol. If you do not make any changes/edits to this section you will need to remove it prior to saving. See screen shots below. You can see the drop down with many Letters each containing a section of the symbol.
If they are empty or you did this by error, you will need to remove these unused sections (corresponding to the letter in the drop down field) prior to saving your symbol. By selecting the Letter and click the remove button as indicated.
Please let me know if this helps.
Customer Support Representative
13626 S. Freeman Road
Mulino, OR 97042