If you are one of the lucky ones to install BSM 2005 Compatibility Release, it is an install that has all the updates built into it, there is a new file that gets written to your C:\Program Files\Common Files\Microsoft Shared\web server extensions\wpresources\Microsoft.PerformanceManagement.Scorecards.WebParts\[version]\BSM.CSS.
This file allows you to change attributes of the style of sharepoint when rendering scorecards. Cool, BUT… It causes a rendering issues with the tabs in SharePoint. If you are experiencing the issues, just rename the BSM.CSS file to something else (BSM.CSS.OLD) and then issue an IISRESET and everything should render just find.
Let me know if you have any questions.