I want to have a table like display on one of panels where the user can fill in data into pre-made columns.  I'm not sure what widget will give me this functionality.  I want users to be able to edit elements they have already added, and to easily add another element.  Any suggestions?
Try ListCtrl with TextEditMixin - it's pretty neat and offers keyboard navigation to move between cells.
Looking for a wxpython widget that would let user's fill in data like they would in a table