I am looking to have 5 items in the drop down, however whenever I add the fifth that becomes the only drop down option. Is there a limit on the amount of drop down options I can have? 

How can I add more marketing channel options to this view? I know how to do it when it's on the vertical axis but am not given the option to display 10 (rather than 5) on the horizontal axis  

I have broken down my unique visitors (total of 56K) to view the marketing channels they came from but the numbers sum to be 59K--how would this happen as I thought unique deduplicates visitors?

I have a dimension with blog URLs that I need to add new URLs to. How can I add these new URLs to this existing dimension?