Windows Explorer Mode & Mozilla
 

I got stumped on the following problem, and having looked for an answer without success, I decided to figure it out myself. If you reckon it's an obvious stupid mistake - I do apologise for wasting your time.

I wanted to list the contents of zip files within UR.

I diligently used [Tools | Options] from the menu, went to the [Browser] page and added ".zip" into the File Extensions to display in internal browser edit box.

When I selected a document info item that had a URL pointing to a ZIP file, up popped a dialog box. It asked me if I wanted to "open with specified application or save to file".

Eventually I figured out that un-ticking the option Use Mozilla/Firefox internal browser control that is located on the [Browser] options page fixed the problem.