Drop down Values in Adobe form

Dear All,

Greetings.

I am using the Adobe interactive form for E Recruitement(copying the standard and changing it as per the requirement). When i am using the Drop down value for one of the field. Instead of the drop down its showing as a POP-UP with all the possible values.

I am not able to predict what the problem is. I need to have a drop down, instead of the pop up.

Please help me in solving the issue.

Thanks

Ram M