I've noticed over the last few days, there has been changes to how shadows are drawn for menus. My understanding is this has a lot to do with menus looking detatched/above unity-launcher, gtk-apps, etc... For a couple days menu shadows were pretty screwed up (some shadows, some not).
Well, now there seems to be some new issues;
1. Menu shadows get clipped when to close to AWN (im sure this is true of cairo-dock too);
I've made the background white, and highlighted the clipped shadow area (which seems to be an area that AWN uses). In the screenshot, you should notice that i am running 'winreflect' plugin (which is unsupported), however, it makes no difference where it has been disabled or removed - winreflect isn't the problem. changes in how shadows are handled is...
2. sub-menus - whenever, you select a sub-menu, than move your cursor away, shadows get clipped and it looks horrible. it basically flickers and leaves no shadow, where the sub-menu once appeared;
the AWN issue isn't super noticable, but the sub-menu issue is an eye-sore.