I have a reporting engine, which (currently) gets configured over XML.
I have seen some of this preview stuff in editors I know, you write some code on an edit tab and the changes get populated when you switch to the preview tab.
This looks rather intuitive to me, since I know it from many tools.
The other idea was to show the preview in a new window, so I could simply refresh it, when the user presses save (or ctrl+s) which could lead to a faster workflow.
Do you have some suggestions about this?