Installed and activated the current version of Google Analyticator (6.3.4) last week and when I went to my Dashboard, noticed that all my widgets were gone! I use Widget Context on my site.
When I deactivated Widget Context and refreshed the page, the problem was still present. The moment that I deactivated Google Analyticator, my Dashboard returned to normal! Just to let you know that I'm apparently not the only person with this problem.
At first, I thought was Widget Context's fault, as that plug-in also had a recent upgrade, but I contacted the developer and the only change in that plug-in's upgrade was a version number.
I've left Analyticator deactivated so that I can continue updating my sidebar widgets.