Hi. At the moment it is very useful for me to have it open, because I come from MacSoup ( I had to change the OS so MacSoup won't work anymore) and I am building my UseNet-Data-Base from scratch. In MacSoup I hadn't such a lot of excluding rules. Now I'm walking through all my news-groups and try to remove all spammer etc. So it would be very useful, when I don't have to close the rules-window after every new established rule. I think, when I have seen all messages in the groups, the spam-messages coming in every day wouldn't be so many, that it is not too uncomfortable to open/close the window. If someone has other experiences (for example: every day minimum 5-10 new spam-messages which are not hit by the existing rules) then it would be nice to have the feature of an open rules-window.
At the moment, I don't have other reasons to keep that window open. (but I'm a new user for usenapp, so I don't know if there would be other reasons to keep it open)
Just my opinion!
Have a nice day and stay healthy!