Jeremy Cook writes:
When you list a an item on Tindie, you can sell a basic product, and also add a variety of options. This could specify the color of a product’s enclosure, whether or not one would like a knob included, assembly, or any number of other services and add-ons. Some of these options may be important enough that you specify that a selection is required, however, there’s a bit of a gotcha here that may not be entirely obvious.
If you specify that a choice must be made, and if there’s only one choice specified, the buyer has to select it before making a purchase. So in the example below, the buyer is required to buy 90º headers, and has to make a choice between including clear heat shrink or not, as well whether or not to include connector wires.