Hi Roger,
If you're logged in as admin (or a user with the 'select different theme' permission), you can choose a theme that can only be seen by that user.
That should give you the flexibility you're looking for.
Having said that, it's still somewhat dangerous to be working from your live site. Do you have a means of setting up a development environment on your local machine? That would be the preferred approach. More details here: http://drupal.org/setting-up-development-environment
Hope this helps!
Trevor
On 2010-10-17, at 6:12 PM, Roger wrote:
We have one theme, Marinelli working but it has no easy way of adding regions so I want to use mpFree which seems to provide all the attributes I need. Question can I leave the marinelli theme working and on line while developing the mpFree theme.
If so how can I switch between themes to see what needs adjustment. Both would use the same database and content.
I'm stuck and would appreciate assistance Thanks Roger -- [ Drupal support list | http://lists.drupal.org/ ]