WTreeView scrollTop is not preserved
When sorting a tree-view, it can happen that the scroll position is lost.
When sorting, the html of treeview is first entirely deleted and then later re-assigned. In some cases, the browser will synchronously process DOM changes, for example when the clientHeight of an element is used somewhere, it will first process all pending DOM-changes to calculate the most accurate result. When this happens in between deleting and re-building the tree-view, scrollTop is lost.