This is a long winded way of saying that I decided to implement another feature first to make it easier for me to test refresh out, editing an existing database. The first step of this was to be able to add columns. So I added an "add column" button.
I used quickly.prompts to get the string from the user. To actually add the column required a bit of intimate knowledge of the internals of DictionaryGrid. It occurred to me that folks might want to be able to add a key/column to a Grid themselves, so I logged a bug to remind me to make this easier.
Since Fagan asked to see the code when I posts :) -
def add_column(self, widget, data=None):
response, val = prompts.string("New Column","Please select a name for the new column")
if response == gtk.RESPONSE_OK: