Hi I would like to create a drop down list that reduces as selections are made from it so that the selections are placed in an order and each selection is only used once.

For example - Possible selections:- Apple, pear, orange, grape

1. Choice of Apple, pear, orange, grape (Grape selected)
2. Choice of Apple, pear or orange as grape has already been used. (Pear selected)
3. Choice of Apple or orange...........Etc.

I have made the drop down list but I am struggling with the content control of the drop down list. Any help is appreciated.