Pressing the back button in mozzila 1.03 seems to reload my command object and prevents me from handling duplicate form submission. Is the back button suppose to reload command object ?

The url I am using is as follows
http://localhost:8080/app/editUser?userid=1

Ever time I submit the form and hit the back button it reloads the backing object so when I submit again all is well when infact I should get a duplicate form submission.