Page-Post Dashboard Issue
The Pages-Posts plugin does seems to affect the stylesheet of the WordPress Dashboard.
Using WordPress 3 or 3.01 on different blogs with different themes installed, I can turn this on/off by enabling or disabling the plugin.
Browser: Google Chrome, plugin deactivated (normal dashboard)
Browser: Google Chrome, plugin activated
Browser: Internet Explorer 7, plugin deactivated
Browser: Internet Explorer 7, plugin activated