Crystal Report 2013 - Color Highlight Problem

Dear all,

I am now using Crystal Report 2013 SP7 (Version 14.1.7.1853) to design a report file (.rpt).

The report includes a bar chart with Layout by Group and the Data is shown as:

On change of:

a Date field (Transaction.Date) and a String field (Transaction.Group)

Show:

Sum of a Number field (Transaction.Amount)

As I want to control the color of the bars, I goto Chart Expert->Color Highlight and try to add items in Item List (which is empty now).

When I click the "New" button, it always prompt the warning

Please enter a datetime value.

For example: "D/M/YYYY H:MM:SS".

and I cannot add any item on Item List.

I think I should enter something in Item editor in "D/M/YYYY H:MM:SS" and press "New" may solve the problem, but the textbox in Item editor is disabled if there is no item on Item list

How can I solve this problem?

Thanks.

Stephen YIP