Thank you for contacting us.
I couldn't reproduce what you reported as improper behavior. Please take a look at the video
and let me know if the steps you performed were different. Also, is it possible that your website is in multilingual and when deleting the child pages of the group pages you somehow only deleted children of one language versions. In this case you won't be able to delete the group page, even if it doesn't have children itself. You need to delete the child page of its translated version first, otherwise you'll get a warning message, which states that you can't delete a parent page, without deleting its child page first. The reason is that when two pages are synchronized they represent one node. Thus, even if you have a child page only under one of them, it still means the node has a child page, which needs to be removed, in order to be able to delete it.
Let me know if you have additional questions.
the Telerik team
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