When deleting a tree node, the children are not removed from the tree view even though they are no longer present in the data. I've ran into this issue in a bigger project, but here is a simple example:
https://1drv.ms/u/s!AvsEaC7oMEMaguF0w1pSmkATdnL4ug?e=znvDuA
Just delete the node 'a'. 'b' will just move under 'c' instead of disappearing.
The data will be written to the console.
Note that there is also a similar bug when removing multiple children of a single node one by one. It's most likely the same bug, so I didn't make an example for it.