Input_AutoComplete_GetIdentifier retaining identifier

Input_AutoComplete_GetIdentifier retaining identifier

  
Hi,
I am using Autocomplete widget and I have an issue with the validation for invalid input.

1. If I type invalid value initially Input_Autocomplete_GetIdentifier retunr empty string (I expect -1 ???)
2.If valid entry is selected and then new invlaid value is typed in identifier will return last valid selected identifier (retaining old valid id) instead -1.

PreviousIdentifier property is set. This is V. 9.0.1

Any hint or advice how to do this properly?