I've seen some other threads on this topic, so here's my example scenario. If you have a Window with an OK button with IsDefault=true, and you show the window in modal mode (dialog), the Enter key is supposed to be able to dismiss (close) the dialog. Unfortunately, if there's a RadTreeView in the window, which has keyboard focus, and the selection is on a node that does NOT have any children (so can't be expanded/collapsed anyway), the RadTreeView eats the Enter key and the window is not closed automatically. (Look at the ToggleExpandCollapseCommandCanExecute method, canExecute is set to true whether the RadTreeViewItem has Items or not).
I know, there's a super-easy workaround and that's to override OnPreviewKeyDown or OnKeyDown in the window code behind, which I'll do, but, the point of posting this thread is that this is not how Microsoft's TreeView works. They don't care about the Enter key probably precisely for this reason. Maybe provide a property to enable/disable this Enter key behavior would be nice.