Unable to Choose (Field Type) in (Appearance) section under (Field Properties) on (Form Builder)

Unable to Choose (Field Type) in (Appearance) section under (Field Properties) on (Form Builder)

We developing a application like Inventory Management using creator from this we have an issue Unable to Choose (Field Type) in (Appearance) section under (Field Properties) on (Form Builder). we have to choose the field type=Submit , then only we write the code on submit button onclick action. so please give us a solution to solve this issue.