You can adjust this setting in Sharepoint.
TLDR; Central Administration > Manage Service Applications > PerformancePoint service application > PerformancePoint Service Application Settings : Edit the number on Filters (Maximum members to load in filter tree).
Start by going to Central Administration.
http://yoursever:6999/default.aspx
Go to "Manage Service Applications"
Then choose performance point.
Once in , select PerformancePoint Service Application Settings.
Set desired maximum size.
