When clicking on urls with right mouse-button in Netscape, you are supposed to get a meny. In Winston you have to hold down the right mouse-button and move the mouse at the same time to get the menu. If not - it works as "back"-button.
This defect is considered MUST-FIX for Winston Release-Candidate #1 (I believe this was fixed but we need to close this defect if this is the case).
I can't reproduce this here in beta5 - are you still seeing it?
I have seen this bug in Winston up to beta4. In beta5 - Pinstripe - I can't see it anymore.
OK, so removing the app-defaults file solved it. Fun.