How can I view the WMClass attribute of a window in Xorg (linux)?

Question

I am trying to find a workaround for incorrect grouping of windows in Docky, and I believe the problem lies with the WMClass attribute that is set for each window. However, I do not know how to view this attribute for open windows. Is there any way to do this?

Answer 1

 %> xprop WM_CLASS

and then click the window in question