Thomas, can you take a look at this? I haven't fully wrapped my head around LayoutImplIE6, but it seems to be setting up several expando properties that are either not unset on detach (__styleRuler) or setup pre-attach (__layer) and so not detached if the user just instantiates the widget but doesn't attach it.
I put some comments in the patch that highlight what I'm concerned/thinking about. I'm not sure if there's an easy way to defer setting up the expando properties until onattach, or if it's worth doing. I was going to start trying to do that, but thought I'd stop and ask for a sanity check first. http://gwt-code-reviews.appspot.com/1601804/ -- http://groups.google.com/group/Google-Web-Toolkit-Contributors
