TreeView messes up its layout when inserting a new item after an open item branch

Steps to reproduce:
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• Run the sample attached
• see image 'treeview_bug.png' for additional information

Phase 1:

• Open 'item 0' branch to reveal 'subitem 0'
• Click button 'insert'
  EXPECTED: the inserted item appears between 'item 0' and 'item 1'
  ACTUAL: the inserted item appears on the last row

Phase 2:

• Make a selection from 'item 0' to 'item 1' using mouse and SHIFT
  RESULT: the inserted item gets selected too -> something wrong with the layout

For comparison, test without revealing the subitem.