Enable the ability to cancel / re-choose said-resource choice from selection menu
Once you pick / give up any resource for the selection menu, you can't cancel and then change your choice. Once you pick / give up resources from said-development card or Cities & Knights cards, then the final choice can never be reversed.
Please fix this immediately. Make it so you can cancel and then choose another resource of your choice from the menu selection screen whenever that this is an option.