>I did try checking that. But what I found was that I first get the regular login window. Then when I login, I get another window with the threads. Then when I click Forum Main Page, I get a third window .. it didn't use the first window, which is what I thought it would do.

No, we didn't name the original window. Thus, the upper toolbar fires up a new window. If it would fires up in a previous window, it would confuse too much. That is why it goes in _blank.