Steps to Reproduce

1. run the zul
2. sort the tree by clicking the "description" column twice
3. open any treeitem

Current Result

cannot open a treeitem

Expected Result

can open a treeitem

Debug Information

• 8.5.1.3 works
• 8.5.2 or above has this bug
• when this bug happens, the clicking treerow.desktop and treerow._node are both null.
• this bug is caused by the fix of ZK-3976

Workaround

• tree.invalidate() but produce open treeitem.