Shortcut for new rows, and column descriptions

So, it would make my workflow in Coda better if it had a shortcut in the keyboard for adding a new roll while edditing the current table, maybe that already exists, but I’m unaware. Also I think it would be helpful if when adding a new column I could add a description for the column itself so when I hover my mouse over the column name I woul get the description I wrote (kind of when you hover your mouse over an option from a lookup list and it shows you the row information for that option, you know? With that little box on the mouse arrow?)