i need to use my own calendar control that is different from UltraCalendarCombo/UltraDateTimeEditor or default calendar. Mr. Mike give the solution like:

'If you have your own custom calendar control, then you could create you own calendar dropdown using one of the existing editor control, like UltraTextEditor, by adding a DropDownEditorButton to the ButtonsRight collection of that control. You would have to handle any interaction between the text portion of the control and the control on the dropdown, of course'

but i did not try this solution yet.