Hi Dieter Schmitz,
I understand... - It is a valid scenario. We will see how to improve the API so we can set a flag to the node that initiated the events.
for the moment I recommend you to turn off
the tri state mode and to check the child items manually when a parent is checked.
I added 1000 Telerik points to your account and added this scenario as a backlog item.
Let us know if you need more help.
the Telerik team