Autodetected metamodels are sometimes not listed when adding a LocalFolder

Moved from Bugzilla:

https://bugs.eclipse.org/bugs/show_bug.cgi?id=563728

In some cases, the Metamodels page is not appropriately updated when a LocalFolder with models with new metamodels is added. The user will switch back to the Metamodels page, only to see an empty list. Closing and reopening the configuration dialog shows the indexed metamodels normally.

This sounds like a timing issue, but it would need to be further investigated.