Fixing Issue #235 TreeView problem with overwriting selected values at Loaded event with default Items[0] value and not selecting TreeItem because Item was selected before TreeItem was because WPF is LazyLoading TreeItems for Items after Loaded event...
Added comments to code
Removed part for delayed selecting of VisualItem because it should be solved more generally for all cases. So this pull now only contains fix for issue #235
Merge pull request #253 from DavidKarlas/Issue235

Fixing Issue #235