Custom form on application have button, the .fmb have no button ???

Dears,

i have an issue in custom form that x developer do, when i get the source of this form i discovered that haven't any button on it. when i run this form on application i found more button. where this button ??

the consultant of module told me that i can control (show,hide) this button with custom profile option.

any information for this issue.

Thanks in advance