There seems to be a variety of Waves GUI glitches in various plugins, but here is an example of how Waves Loudness Mater WLM Plus appear when I first insert it into the Post-Processing slot, and an example of how it should look which I can make happen after clicking another tab and going back.
WLM Plus seems to load OK in the master section slots or a clip effect slot, but is especially problematic in the post-processing slot.
OSX 10.9.2
WL 8.5.10
iMac 27"
32GB RAM