I'm building quite a big data model from a complex CRM Online data source, which requires a lot of table editing, merging, etc. Starting frm yesterday I started to notice that I cannot see tables preview anymore. It just keeps loading all the time, and nothing happens. However, when I click "Apply Changes", it takes some time but loads successfully.
What could be the probably cause of preview freezing?
UPDATE: also problems when adding a custom column now, it just keeps thinking for infinite...