Non required date field doesnot show clear button

Hi,

We observer that a non-required date field does not show clear button but the required date field shows a clear button. 

It should be other way round.

We checked the SDK code and found that the code written in app/js/fields/date/date.js under toggleControls is having this problem.

toggleControls: function() {
        var isEmptyValue = _.isEmpty(this.getValue());
        this.input.toggleClass('empty', Boolean(this.def.required && isEmptyValue));
        this.clearButton.toggle(Boolean(this.def.required && !isEmptyValue));
        if (this.def.required && this.placeholder) {
            this.placeholder.toggle(isEmptyValue);
        }
    },

On line number 4 it should be 

this.clearButton.toggle(Boolean(!this.def.required && !isEmptyValue));
        

Joe Mao