But what's so surprising is that I don't remember the Windows client to be nearly as bad as the one for Mac. I guess they are made by two completely different teams with no coordination on UI issues.
http://www.disruptivetelephony.com/2011/04/my-3-main-issues-...
They are trying to get better at this and with their latest 5.x releases are trying to come out on at least Windows and Mac OS X at the same time with similar features.