What's the difference between Show and Hide for rows/columns (apart from the obvious)? The answer is how the module behaves when new items are subsequently added. So, if I have a module with 10 line items, and only want to see 5 by default then I could...
- select the ones I don't want to see and select 'hide'....the module is now behaving as 'show everything except for those specifically hidden'
- select the ones I do want to see and select 'show'....the module is now behaving as 'only show the items specifically selected to show'
Now I add a new item into the module. It will appear in the grid if I'd previously hidden other items, it wont appear in the grid if I'd previously shown some items. Getting it right at the outset means no more having to 'show all' and then respecify your hides/shows, and no more having to republish modules to a dashboard. Acknowledgments to Martin Overton for making me think about some behaviour which I'd seen many times before but never thought about what was actually going on.