Data in the combobox is reapeting. How to solve this?

Good day!

Any oidy help me so that the data inside in the combo box will not reapiting?
Scenario:

  • I have two frames in the first frame there is a combobox with three label.(one,two,three)

  • If i click next button it will go to the 2 frame then if click the previous button it will go o the 1st frame but the problem the data inside in the combo box will be reapeted (one,two,three,one,two,three)

  • how to make that if you go back to the 1st frame the data in the combo box will not repeated?

My Code is in here:

cmb_type.addItem({data:1, label:“Bar Shape”});
cmb_type.addItem({data:2, label:“L Shape”});
cmb_type.addItem({data:3, label:“Island”});

thanks your help will greatly appreciated.