Issue 2: When I use a custom value I expect it to bind to the model _selectedLot but after entering a custom value _selectedLot is still empty and i have to retrieve the custom value using the following code. 

let element = $("#avilablelotDS").igCombo("textInput");
this._customLot = (<HTMLInputElement>element)[0].value;

the selectionchanged event is not getting fired when a custom value is entered. 

Hello Deepti,

After looking into that, the recommended approach is to handle the input event binding for KO for the igCombo.  The selectionChanged event will not fire since the selection is not changing when typing a custom input.  That was an oversight in my last response.

Using this method also negates my previous answer and you would need to use the following code in your ViewModel to get the value:

In your ViewModel:

function ViewModel() {
    ...
    this.lotSelectionChangedEvent = function(vm, evt) {
        this._customLot = $(evt.currentTarget).val();
    },
    ...
}

In your markup:

<input id="koCombo" data-bind="igCombo{
    width: '100%',
    height: '25px',
    caseSensitive: false,
    compactData: false,
    dataSource: colors,
    placeHolder: ' ',
    highlightMatchesMode: 'multi',
    hideEnterKey: false,
    selectedItems: _selectedLot,
    tabIndex: -1,
    selectedItemType: 'object',
    itemTemplate: '<div class=\'comboTemplate\'><div class=\'comboInfo\'><span class=\'emphasizedText\'>${Lot}</span></div></div>', 
    textKey: 'Lot',
    valueKey: 'Lot',
    mode: 'editable',
    allowCustomValue: true
}, event: { input: lotSelectionChangedEvent }" />

If you have any further questions with this, please let me know.

Please let me know if u have an ETA for the case.