Contact list and conversation script menus, plus any other menus that follow the Plus! theme on a WLM window are all affected (i.e. Plus!-style menus originating from a Plus! window are not affected). Also missing the Plus! menu bar item in the contact list but not conversations.
Had this issue only since today. Latest Plus! and WLM 2011.
Just to clarify, my name/contacts aren't affected, I just didn't show them in the screenshot.
Edit: turns out it's a problem with the Enhancer script on WLM 2011... uninstalled and we're back to normal.