After searching a topic I get a list of results. After clicking on one and then trying to hit the back button I lose my search list and have to search again. Is this a feature or design flaw?

It's just the way browsers work, it's not a design flaw, or really anything to do with the design of the search function. Look here for a more complete answer.

Each time you go to a search result, open it in a different window.

That way the original window with the search results won't be supplanted by the page you go to.