Deploying PerformancePoint Server Monitoring & Analyzing content from one server to another
If you're developing PerformancePoint dashboards, you'll probably run into the situation where you've developed your dashboard on one server and would like to deploy it to another server... opening your .bswx file and trying to publish all changes will not work 
... This is where the 'Mark differences' button comes into play!
Use it after you've opened your .bswx file and refreshed the workspace (don't accept Dashboard Designer to overwrite your workspace files with the files from the server!), and it will compare the content of each workspace file with the content located at the server. It marks all the files with different content. When it's finished, simply publish all items to the server and you're up and running again 
!