I have a problem that seems to have started with 2.9.1 I use around 30 plugins (I know its a lot, but many are small and serve only a minor function I need) and for some odd reason once I enable around 25 the dashboard begins to break the Incoming Links, WordPress Development Blog and Other WordPress News widgets, one at a time.
When I enable 26, the incoming links stops working and only says Loading... If i disable something it works again. If I enable 27 the WordPress Dev stops working as well and 28 and all 3 stop. The more I enable after that, it becomes difficult to move dashboard items from one side to the other, they will not show the placement box for more than a split second.
I'm not sure what to think of this, I have disabled all plugins and slowly restarted them, it doesn't seem to matter what plugins it is, simply how many. It may also be related to Memory Usage, as I have a plugin that tells me how much I am using, and every time around 85% this happens. Not sure which it is, # of plugins or memory use, as they both hit around the 85% mark around the same amount of plugins.