1.select '01', the selItem change to item01
2.in combobox, delete char '1', and tab out. you will see a warn, and the selItem is still item01
3.in combobox, delete char '0', wait, you will see the value of combobox become '01' again.
1.select 01, the selItem change to item01
2.When delete char '1', and tab out. it fires onChange, the validator block the update, so, in combobox the selection is null, but in model it is still item01
2.1 when delete char '1' onChanging -> onAfterRender, selItem is already in model's selection set, so the combobox string doesn't be reload
3.When, delete char '0', combobox fires onChanging and this cause combobox fire onAfterRender, and triggers zkbind load selItem to model, and this cause combobox to reload the selected value to '01'