disable popup of jquery datetime pciker when focus on textbo

I am using jQuery DateTimePicker plugin from http://xdsoft.net/jqplugins/datetimepicker/. I don't want to open the calendar popup when focus on textbox instead of that i want to give some image button at the end of textbox and when user clicks on image button then only calendar popup should open for date time selection. When focus on textbox user should be able to enter manually. if popup is coming sometimes popup is coming on above textbox so we can't see anything in textbox to enter manually.

 

I am using jquery datetime picker not only date picker.