I am not certain what you are clicking on to get what you are seeing, but it should say "DSP Studio" on the top title bar of the window. The window for Plug-Ins is a different window all together and if it says "Plun-In Manager" on the title bar you are in the wrong place.
When I click on the DSP Studio (right-most button next to Repeat and Shuffle) I get a drop-down menu with option for DSP Studio. That opens a new window that offers functions along the left side (Effects, Volume Leveling, Analyzer, Room Correction, etc) and it changes size depending upon which of these functions I select.
It is one of the images displayed on the Wiki here:
http://www.jriver.com/audio.html(I think it is like the 3rd one, just before the headphone image)
The window for Plug-Ins is a different window all together