AddNode expands all level 1 nodes

[jordib123]

I have a treeview of top level nodes (see image 1), when clicking on a node, I do an AJAX request to obtain all child nodes of the clicked node and append them to the node using the AddNode function (see image 2). This works perfectly fine, however, when I collapse the node (see image 3) and add new children (obtained by AJAX using AddNode) to a different node, it automatically expands all top level nodes instead of only the parent node I just appended the children to (see image 4).

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Image 2:

Image 3:

Image 4: