I installed WP 2.5.1 a few weeks ago and have tried a few different themes, without any problem.
But suddenly, as I was trying a new theme, something went wrong with the Design->Widgets page. I don't see any of the widgets being used in the "Current Widgets" list, nor can I add any new widgets.
This is the same with all the themes that I have tried so far at this point (even with the default theme and others that worked flawlessly before).
It appears like something to do with "dynamic sidebars" has gotten corrupted. I am looking for any pointers that will help me debug this. If I had to restore some WP files to fix this, which ones should I start with?