QMM fails to expand (open) a container during migration session when selecting objects in source (4353496)

When you create a new migration session and press select and then click on the plus sign to expand the OU it will stop loading.
Please see also attached screenshot which demonstrates the problem.
This happens only once when you do it for the first time, it doesn't cause any inconvenience and can be safely ignored.
During second attempt (mouse click) the same OU or container will be expanded successfully.

Quest development is aware of this issue and will try to resolve it in future releases of QMM.
An official Enhancement Request (Change Request) ST58484 has been created.

There is another known issue ST81918 where target scope cannot be expanded by clicking on the squares next to OU names. This happens every time a migration is performed or the target domain structure is browsed. When clicking the tree nothing happens at all. This can be worked around by double clicking on the actual OU name to expand it.