Interntet Explorer 11 freezes by using Nested Cluster Diagram in the interactive client.
Removing filters or coloring options in the legend of the Nested Cluster Diagram in the interactive client can cause a browser freeze if you use Internet Explorer 11.
As workaround please refresh the browser page or if possible use another browser. After refresh all configuration will remain.
Manipulating the "children" relation of building blocks using PUT requests of iteraplan's REST API can cause data inconsistencies. (fixed in 5.0)